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2003
PRODUCT GUIDE
STATE-OF-THE-ART TECHNOLOGY. EASY-TO-USE FEATURES. READY-TO-USE COMPONENTS.
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t Celestron we are proud of our 40 years of experience as a leader in
the telescope industry. Recently a new era began for us when the
company’s senior management team purchased Celestron. This is our first
major new product catalog as a new company and we have invested a lot of
our time and energy into making it an effective tool to navigate through our
extensive product line.
In this new catalog, we are taking a new approach to the way we present
our product information and specifications. Just like our approach to product
design, our intent was to make this catalog easy to understand and userfriendly, while at the same time filling it with advanced features and
information that speak to the entire spectrum of our audience. We are
continuously trying to break new ground in the areas of product development
and design, and we feel that this is reflected in the development and design
of this catalog.
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Each of our product families is introduced by a divider page that serves
as an overview of the product line with details on special features. This is
followed by the product pages that break down all basic specifications,
standard equipment and recommended accessories for each telescope model.
A specification page that provides detailed technical information for each
product family follows each section.
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One of the unique challenges we faced was making this catalog a useful tool
for all astronomy hobbyists, from the advanced to the novice. For the novice
we begin the product guide with a section titled Telescope Basics which
contains information about amateur astronomy including what you can see,
how telescopes work and what to look at. If you’re looking for your first
telescope, this guide will help you with the different choices. And for
experienced hobbyists wishing to weigh the benefits of upgrading to a more
advanced model, or to expand your hobby to include astrophotography, this
catalog includes information designed to address questions and concerns.
We are also proud to announce the implementation of a new warranty
period. As of March 1, 2003 we now offer a two-year warranty on all
imported and self-manufactured telescopes. For details on our warranty,
contact Celestron or visit our web site: www.celestron.com
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Table of Contents
History of the Company
001
Quality
002
a. Engineering
i. Process
ii. Components
iii. Quality Assurance
b. Optics
i. Process
ii. Components
iii. Quality Assurance
Telescope Basics
i.
ii.
iii.
iv.
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General Information
Terms
Mounts: Advantages / Disadvantages
Types of Telescopes: Advantages / Disadvantages
Product Sections
i.
Firstscope
009
ii.
Advanced Series
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®
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®
iii. NexStar GT
iv.
NexStar i
028
v.
NexStar ® GPS
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vi.
CGE Series
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vii. Optical Tubes
044
viii. Astro Binoculars
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Appendix: Astrophotography & CCD’s
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Glossary
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History of Celestron
elestron began in the 1950s as Valor Electronics, an aerospace electronics firm. Celestron’s founder, Tom
Johnson, became interested in telescopes and astronomy when looking for a suitable telescope for his two
young sons. Tom decided to build a telescope from scratch. Starting with a 6" reflector, he progressed to building
increasingly larger and more sophisticated designs. Tom’s hobby soon grew into a full-time business, offering
Schmidt-Cassegrain telescopes in 4" to 22" models.
His immediate challenge was to find a way to efficiently produce the Schmidt corrector plate used in our top-ofthe-line catadioptric telescopes. Although a corrector plate appears flat, it actually has a “wavy” surface that’s
difficult to mass-produce using standard equipment and procedures. Making Schmidt correctors was an expensive
and time-consuming process.
In 1970 our designers and engineers announced a revolutionary method of producing Schmidt-Cassegrain
telescopes at a reasonable cost and in volume. This optical breakthrough was incorporated in the first Celestron C8.
The popularity of the C8 in the consumer marketplace led to the C5 and then to larger versions including an 11"
and 14" telescope. The Celestron product line still features 5", 8", 11" and 14" models but has been broadened to
include a number of refractors, reflectors and a complete line of binoculars and spotting scopes.
Celestron has experienced tremendous growth over the years. Incorporated in 1957 as Valor Electronics, Tom
Johnson sold the company in 1980 to Diethelm Ltd. In 1998 the Tasco Corporation, a leading optics company,
purchased Celestron. In June of 2002, three members of Celestron’s senior management, Joseph A. Lupica, Jr.,
Richard Hedrick and co-founder Alan Hale, purchased the company, initiating a whole new era for Celestron. Under
the new management, the company plans to expand distribution channels and product offerings to better serve our
customers.
– First to have an entire Schmidt-Cassegrain line of telescopes in 1969, C6, C8, C10, C12, C16, and C22.
– First to offer a commercially available Observatory Class Telescope with the C16 and C22
– First to commercially offer Schmidt Cameras in the late 60’s.
– First to introduce a fully integrated computerized GoTo observatory class telescope in mass production with the
Compustar 14 in 1987.
– Popularized the Cold Camera in the early 70‘s.
– Popularized piggyback photography.
– Popularized Maksutov-Cassegrain in astronomy with the introduction of the C90 Astro for $495 in 1979.
– Popularized Maksutov-Cassegrains as spotting scopes with the introduction of the C90 Spotter in 1979.
– Popularized eyepiece projection with the introduction of tele-extenders for Celestron’s line of Schmidt-Cassegrains.
– Popularized off-axis guiders for long exposure photography.
– First to offer a telescope drive system that ran off of 9V batteries.
– First to offer a computerized telescope that ran off of AA batteries in 1996 with the Ultima 2000.
– First to commercially introduce a reducer/corrector for Schmidt-Cassegrain telescopes.
– First and presently the only company to offer hand figured Schmidt-Cassegrain telescopes. (We don’t mix and
match correctors.)
– First to offer enhanced reflectivity and transmission coatings with the introduction of StarBright® coating.
– First to commercially offer an 8” fork mounted Schmidt-Cassegrain for under $1,000 with the introduction of the
Celestar.
– First to commercially offer a Schmidt-Cassegrain capable of f/2 CCD imaging with the introduction of the Fastar®
in 1997.
– First to commercially offer Carbon Fiber tubes with Schmidt-Cassegrain telescopes with the introduction of the
NexStar 11 GPS in July of 2001.
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We are proud of our over 40 years of history as Celestron. We continue to manufacture approximately half of
the products we distribute in our Torrance, California (a suburb of Los Angeles) headquarters. We emphasize the
attention to detail that goes into each of our products and the strict quality control standards that are enforced.
In all of these products, our mission is to provide the highest quality optical products at a competitive price.
– First to introduce commercially available Schmidt-Cassegrain telescopes starting in 1966.
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Many people still remember Celestron for its orange color C8’s but many more are now familiar with our other
product offerings. Major colleges and universities worldwide use our telescopes in their astronomy programs.
Throughout the world, Celestron telescopes have always been the “telescope of choice”. Our reputation is so good
in the scientific community that Celestron’s C5 telescope has been chosen over all competing models by NASA to
be taken on several space shuttle research missions.
Celestron has not only been a substantial innovator, but has also changed the landscape of amateur astronomy
with the introduction of the first commercially available Schmidt-Cassegrain telescope. Below is a list of some
innovations introduced by Celestron over the years.
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– First to commercially offer a fully computerized GoTo telescope with integrated GPS and compass with the
introduction of the NexStar 11GPS in July of 2001.
– First to commercially offer a telescope that is GPS compatible with the introduction of the NexStar 5i and 8i in
July of 2002.
– First to offer a GPS with an integrated compass designed to work with a GPS compatible computerized telescope
in Dec of 2002 with the introduction of the CN16 GPS.
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Joseph A. Lupica, Jr., President and CEO; Alan Hale, Chairman of the Board;
Richard Hedrick, Senior Vice President and Chief Technology Officer.
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Celestron Quality: Design, Manufacturing, Service
At Celestron, we want to be known as a company that puts quality first in all aspects of our business. We are a
complete company, working together to make the best possible products backed up by the best possible product
support system. Because of this commitment to quality, we organized our efforts to manufacture products from
the inside out — starting with the most important internal components to the external touches that set the look
of our products apart. This process begins with our extensive engineering expertise.
Engineering
From conception to creation, each product is designed with several key factors in mind. We focus on including
special features that will enhance the experience for the end user — providing superior optics and optical coatings,
high-quality mechanical components, user-friendly ergonomic designs, lightweight materials and following up with
rigorous internal testing and quality assurance. We are consistently dedicating our engineering resources to the
research and development of new product innovations.
Quality Assurance
Each of our self-manufactured telescopes is painstakingly tested for quality, starting in the pre-production process
and must pass several key inspection steps during the production of sub-assemblies. After final assembly, the
completed telescope goes through a series of quality checks. The NexStar GPS models, for example, go through no
less than 25 separate post-production steps before being cleared to ship, some of which are listed in the table below.
Optical Collimation
The inspector collimates the optical system by aligning the secondary mirror
to the optical axis.
Optical Diffraction test
The inspector tests for astigmatism and overall optical performance.
Optical Ronchi Grading test
The inspector tests for overall correction and smoothness of optical figure.
GPS System Communication test
The inspector tests that the GPS is communicating with the rest of the
telescope systems.
Subsystem Communication test
The inspector tests that all of the different electronic boards are
communicating with each other.
Altitude Switch Functional test
The inspector tests the altitude downstop switch for functionality.
Compass Function test
The inspector has the telescope point North to test functionality and accuracy.
Backlash and Guiding test
The inspector tests to ensure that the telescope has minimal backlash and
that gears are preloaded properly so the telescope can be used for fine
guiding during astrophotography.
Orthogonality Tracking test
The inspector tests to make sure the two axes are orthogonal to each other.
Tracking Smoothness test
The inspector tests to ensure that the gears are not binding by looking
closely at the smoothness of the tracking.
GoTo Pointing Precision test
The inspector tests to ensure that all the mechanical and electronic
components are working in concert with each other.
Cosmetic Inspection
The inspector looks at the overall cosmetics of the optics and the paint.
Technical Support
Our commitment to quality does not end when the product ships out. We pride ourselves on providing excellent
support systems for our customers. One of the ways in which we have distinguished ourselves is by having some of
the best technical support resources for our customers. Our Technical Services department is composed of highly
trained operators who are not just knowledgeable about the product, but passionate about the work we do here.
They are committed to answering questions in a timely manner whether over the phone or by e-mail. They work
hand in hand with our Service Department to ensure that customers receive their products back in a timely manner,
and that all concerns are addressed.
Web Site
Another information resource we offer is our extensive web site. Product information is at your fingertips via the
worldwide web at: www.celestron.com. Continually updated, our web site is one of our best resources for customers
wishing to get more detailed information about our products and our company. We also have an extensive section
that contains answers to the most frequently asked questions. We always welcome feedback from customers on
how we can make our site more user friendly.
Many of the parts used in our self-manufactured
products are fabricated in our precision machine shop.
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Our engineering department is also involved in the design and quality of all imported products. To bear the Celestron
name, a product must pass the same rigorous scrutiny and testing that we apply to our self-manufactured products.
We work closely with our vendors to ensure that our standards of quality are never compromised.
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Here our technicians are preparing 11” optical tubes
to be mounted on the NexStar GPS drive bases.
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Optical Quality Process
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Optical Quality
Without a doubt, the most crucial aspect of a telescope is the optics. Celestron is best known for making optics that
are consistently superior. This is because we build quality into each and every telescope with processes that we have
developed over many years.
Optical Components of the Schmidt-Cassegrain
The Schmidt-Cassegrain uses three optical components — the corrector lens, the primary mirror and the secondary
mirror. In the process of manufacturing a complete Schmidt-Cassegrain telescope we have no less than 16 optical
quality checks performed on every telescope that is produced at our Torrance facility.
The result is a diffraction limited optical system. Diffraction limited means that the limiting factor of the resolution
of the telescope system is the wave nature of light itself. In other words, the spot size of the focused light from the
optical system is smaller than the diameter of the central disk of the diffraction pattern created by focusing a star,
also called the Airy disk. Diffraction limited corresponds to about 1/4 wavefront error (1/4 the wavelength of light).
This means the deviation from a perfect surface for our optics is typically around .0000026" or 67 nanometers. In
order to achieve this consistently, we have many optical tests for each component. Some of those quality checks are
listed in the table below.
Here an optician is checking the figure of a primary
mirror. This is a foucault test performed at the radius
of curvature of the primary mirror.
Corrector Lens – After the corrector is manufactured, it is tested
with a match plate to check for smoothness and the correct radius
of curvature. The part is then placed into a double pass
autocollimator where several tests are done. Finally, we visually
inspect the part for cosmetic flaws.
– Match plate
– Knife edge: Autocollimator
– Ronchi grating: Autocollimator
– High power diffraction: Autocollimator
– Cosmetic visual inspection
To match a system, all three components are placed into a double pass autocollimator. This is basically a mock-up
telescope that is twice as sensitive to errors. In the collimator we see any residual errors in the complete telescope
system. The final figuring for the overall telescope is done on the secondary mirror by our team of matching
opticians. This is one of the most skilled departments in Celestron. Each and every Schmidt-Cassegrain telescope
is matched and hand figured by our matching opticians.
Primary Mirror – The primary mirror needs to be produced to a
certain radius of curvature and needs to be smooth with minimal
zonal errors. Then the mirror needs to be precisely mounted on its
focus tube. This is done to an accuracy of better than 30 arcseconds
for every telescope.
– Primary permanent alignment
Secondary Mirror – The primary mirror needs to be produced to a
certain radius of curvature and needs to be smooth with minimal
zonal errors.
– Match plate
System Inspection in Matching – This is the area where all of the
components are first put together. The optical quality is evaluated
as a complete system and improved by hand figuring. In order for
the optics to be finished in matching, the system has to pass several
optical tests designed to ensure that it is a diffraction limited
system.
– Hand Figure: Matching
– Knife edge: Autocollimator
– High power diffraction: Autocollimator
Final Inspection of System – After the optics are installed in the
optical tube, the system is collimated. Once collimated, every
telescope is optically tested to make sure there is no pinching or
astigmatism induced from the mounting process
– Collimation
– Ronchi grating: Test Tunnel
– High power diffraction: Test Tunnel
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Optical Test
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Optical Component
Hand Figuring and Matching
The quality checks listed in this section are one of the reasons for our success. But the final, and most important reason
is that we Hand Figure each system. No other manufacturer in the world produces the number of hand figured
customized optics that Celestron does. Unlike competitors that mix and match the optical components to get a complete
system, we hand figure. Every optical system is evaluated and “touched up” by an experienced optician to minimize any
residual errors of the system. This process ensures diffraction limited optical performance on every telescope.
A matching optician evaluates an optical system in a
double pass autocollimator. After the optician hand
figures the secondary mirror, it is placed in the
collimator with the rest of the optical system and the
whole system is evaluated.
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An optician in the matching department is hand
figuring a secondary mirror. This process is done on
each and every Schmidt-Cassegrain telescope produced
by Celestron. This is the reason Celestron is known for
optical quality.
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Telescope Basics
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n this section of the Celestron catalog we will look at telescopes from the point of view of their separate
component parts. This will help you make decisions when selecting a telescope model for yourself. We will also talk
about the different uses for telescopes, namely for astronomy or terrestrial use. You should read this section if you’re
not sure which of our products is right for you.
Celestron’s telescopes come in a variety of types and configurations. Each configuration offers specific characteristics
optimized for a particular use. Each complete telescope configuration is made of two basic components:
The Optical Tube Assembly
The Mount/Tripod
Limiting Magnitude
Astronomers use a system of magnitudes to indicate how bright a
stellar object is. An object is said to have a certain numerical
magnitude with 0 (the star Vega ) as the baseline. The larger the
magnitude number, the fainter the object. Each magnitude is a
difference in brightness by a factor of 2.51 times. For example, a
star that is considered 5th magnitude is 100 times fainter than Vega, a
zero magnitude star (2.515). The faintest star you can see with your
unaided eye is about sixth magnitude (from dark skies) whereas the
brightest stars are magnitude zero (or even a negative number).
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Besides complete telescopes, Celestron also offers some models of these components as separate products you can
integrate with other elements you may already own.
What is a telescope?
A telescope is simply a light collector. It has one task: to form the brightest possible optical image of the object on
which it is focused. This task is accomplished by the primary optical element (or simply the primary) inside the
telescope tube. Primaries are either lenses, mirrors or a combination of both. The image formed by the primary is
then magnified by a removable component called an eyepiece. By using different eyepieces, you can change the
magnification and the field of view of what you see through the telescope.
What can you expect to see with your telescope?
You might think that the magnification, or power of a telescope, is its most important function. Well, it’s not. The
most important characteristic of a telescope is its light gathering ability. The light gathering capability of a telescope
is determined by the size of its aperture (diameter). The larger the aperture of the primary of a telescope is, the more
light it collects. When looking at a bird or the boat across the harbor, it’s the light gathered that makes the image
brighter and easier to see. When looking at a star or galaxy, it’s especially important that as much light be gathered
as possible. Fainter celestial objects may be invisible to smaller aperture telescopes. Without enough light, dim
objects cannot be seen, no matter how much they might be magnified!
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The relationship between a telescope’s light gathering power and the diameter of its lens or mirror is not directly
proportional. As the diameter gets larger, the amount of light gathered increases by the square of the diameter. So if
you double the diameter of the primary lens, its light gathering ability increases by four times!
When comparing telescopes, there are a number of characteristics that can help quantify their differences. The most
common ones are: Light Gathering Power, Limiting Magnitude, Resolution and Magnification. No matter what
optical designs you compare, these characteristics provide valuable information as to what you can expect to see
through a telescope.
Light Gathering Power
Light gathering power is defined by the surface area, or light collecting area, of the primary lens or mirror.
To calculate the
light collecting area:
For an 8” primary:
For an 4” primary:
Light Collecting Area = πr2 (where π = 3.1416 and r = the radius of the primary)
Light Collecting Area = 3.1416 x 42 = 50.24 square inches
Light Collecting Area = 3.1416 x 22 = 12.56 square inches
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By expressing the light collecting area of both primaries as a ratio you can determine their light gathering power.
50.24 square inches/12.56 square inches = 4
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So, an 8” telescope has 4 times the light gathering power as 4” telescope.
The faintest star you can see with a telescope (under excellent seeing
conditions) is referred to as the limiting magnitude. The limiting
magnitude of a telescope is directly related to aperture, where larger
apertures allow you to see fainter objects. A rough formula for
calculating the visual limiting magnitude of any telescope is: 7.5 + 5
LOG (aperture in cm). For example, the limiting magnitude of an 8”
(20.32cm) aperture telescope is 14.0.
Limiting Magnitude =7.5 + 5 LOG 20.32 = 7.5 + (5x1.3) = 14.0.
Atmospheric conditions and the visual acuity of the observer will often
reduce limiting magnitude.
Object
Visual Magnitude
Sun
-26
Full Moon
-12
Vega
0
Andromeda
3
Pluto
14
This table shows the Visual Magnitude for various
popular objects
Aperture
Light Gathering
Power versus
naked eye
(7mm)
Limiting
Magnitude
60mm
73x
11.4
114mm
265x
12.8
5”
329x
13.0
8”
843x
14.0
14”
2581x
15.3
This table shows the light gathering capability and
limiting magnitude of different aperture Celestron
telescopes.
Resolution
Resolution is the ability of a telescope to render fine detail: Higher
resolution lets you see more detail on the surface of a planet or
separate stars that are close together. Resolution is measured in terms
of degrees of arc (called degrees), minutes of arc (called arcminutes),
and seconds of arc (called arcseconds). Thus, something that spans one
degree of arc is also 60 arcminutes, or 3600 arcseconds (60 x 60). So,
something that is one arcsecond is very small — only 1/3600th of a
degree.
Resolution for a given telescope is calculated using the formula:
Object
Angular Size
Full Moon
.5 degrees (1,800 arcsec.)
Jupiter
~30 arcseconds
Mizar/Alcor
14 arcseconds
Epsilon Lyra
2.5 arcseconds
Cassini Division
of Saturn’s rings 0.7 arcseconds
The angular size of some common celestial objects.
Resolution = ((1.22 x ) / D) x 206265
Where resolution is in Radians, is the wavelength of light (.00055mm
for common visible wavelengths), “D” is the diameter of the primary in
millimeters and 206265 is the number of arcseconds in one Radian.
Aperture
Resolving power
60mm
2.31 arcseconds
102mm
1.36 arcseconds
Most commonly, light gathering power of a telescope is compared to the light gathering ability of the human eye.
The average healthy person has a fully dark-adapted pupil size of only 7mm, or slightly over 1/4”.
8”
0.68 arcseconds
14”
0.39 arcseconds
Using the same formula to calculate the light collecting area of a 7 mm pupil you can see that an 8” telescope has
843 times the light gathering power of the human eye!
Selected Celestron telescopes and their resolving
power.
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Telescope Basics
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Do you want to do long exposure astrophotography?
A 1.5 arcsecond binary star pair seen
through a 60mm telescope
through a 102mm telescope
through an 8” telescope
Altazimuth mounts are the simplest type of mount with two motions, altitude (up and down/vertical) and azimuth
(side-to-side/horizontal). Good altazimuth mounts will have slow-motion controls to make precise adjustments,
which aid in keeping tracking motion smooth. These type mounts are good for terrestrial observing and for scanning
the sky at lower power but are not for deep sky photography. Many Celestron altazimuth mounts are now computer
driven and allow a telescope to track the sky accurately enough for visual use but not for long exposure photography.
The highest magnification you can reasonably achieve with your telescope
is once again determined by the size and light gathering ability of the
primary. The practical limit is about 60 times the diameter of the primary
in inches. So, an 8” telescope should not be expected to produce
reasonable images if the telescope/eyepiece combination produces a
magnification greater than 480x. In practice, the amount of magnification
that can be used will often be reduced by atmospheric conditions.
Aperture
Highest
Usable
Magnification
60mm (2.4”)
142x
102mm (4”)
241x
5”
300x
8”
480x
14”
840x
Highest usable magnification(power) for selected
telescope sizes.
To calculate magnification:
(Focal Length of Primary in mm)
Magnification = —————————————
(Focal Length of Eyepiece in mm)
So, for a NexStar 8 using a 25mm eyepiece:
An example of an altazimuth mount
If you want to follow the stars and planets as they appear to move across the sky due to the Earth’s rotation, you
will need a telescope that tracks. If the telescope does not track, whatever you’re looking at will drift out of the field
of view in a matter of seconds. The higher the magnification, the faster the object drifts. Both altazimuth and
equatorial mounts can track the stars sufficiently for visual use, however, only equatorials can be used for long
exposure astrophotography. Since altazimuth mounts are not aligned with the Earth’s axis, they must use both axes
to track an object. With altazimuth mounts you will be able track accurately on an object centered in the field of
view, however over time all the other stars in the field will appear to rotate around the center of the field. This is
hardly noticeable in an eyepiece, but is obvious on film.
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Since many astronomical objects are relatively large but faint, moderate magnification and a larger diameter primary
to gather light is the best combination for viewing most celestial objects. When looking at stars, high power is of
little use since they always look like pinpoints (they’re so far away they can not be resolved as anything other than
a pinpoint).
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From the table you can see that the 60mm aperture telescope does not have the resolving power to “split” the two
individual stars in this binary star. A 102mm telescope can just barely split the close pair, and an 8” or larger
telescope can easily resolve the two stars in the binary.
Magnification
Magnification, frequently referred to as “power,” is a function of the focal
lengths of both the primary and the eyepiece. The focal length is the
distance from the primary lens or mirror to the point where an image is
formed. The eyepiece magnifies the image formed by the primary.
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Altazimuth vs. Equatorial:
To a large extent, a telescope is only as good as its tripod and mounting. A telescope magnifies everything, including
vibration. That’s why many telescopes with decent optics are rendered useless when supplied on a cheaply made
mount. The mount’s adjustments should be smooth, yet precise, as you’ll be using them to track the slow and steady
apparent movement of the stars. Smooth and precise movements (and a motor drive) are an absolute requirement
for astrophotography.
Altazimuth Advantages
– Easy to setup and use.
– Less expensive.
– Ideal for terrestrial observing.
Altazimuth Disadvantages
– Cannot be used for long exposure photography.
– Cannot track stars and planets.
Magnification = 2000/25 = 80 times the power of the unaided eye.
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Telescope Basics
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make excellent scopes for looking at birds or spotting whales. Most Celestron altazimuth mounted refractors come
with an erect image diagonal or eyepiece to correct the inverted view and allow you to see land objects right-sideup. Newtonians, on the other hand, produce a rotated view of land objects due to the position of the eyepiece and
are not recommended for terrestrial observing.
Choosing a particular telescope depends on your individual needs including cost, portability, versatility, usability and
appearance. You should also contemplate what you plan to do with the instrument both now and in the future.
Considering your budget and portability requirements, select a telescope with as large an aperture as possible.
Now that you understand some of the factors that distinguish different telescopes from each other, here are the
details of the different optical designs Celestron offers:
Types of Telescopes
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Example of an equatorial mount
On an equatorial mounting, the two axes are perpendicular to each other as they are on an altazimuth mount. But
on an equatorial mounting, the left-to-right axis has been tilted so that it is parallel to the Earth’s axis instead of at
the horizon. On an equatorial mount, only the axis that is parallel to the Earth’s axis, needs to be rotated. On an
altazimuth mount, BOTH axes must be moved.
Some of Celestron’s telescopes are on altazimuth mountings; others are on equatorial mountings. The computerized
versions that are mounted on altazimuth mountings include a computer that moves the telescope in both axes to
compensate for the earth’s rotation, and this works just fine for visual use. But if you want to do long exposure
photography, the telescope must be mounted on an equatorial mount. The Celestron telescopes that are on
altazimuth mountings can be tilted up (with the use of an equatorial wedge) to orient the azimuth axis parallel to
the Earth’s axis.
Refractor
A refracting telescope uses a lens as the primary. The lens at the front of the telescope bends the light passing
through it until it comes to a single point called the focal point.
The long, thin tubes of refractor telescopes look much the same as those Galileo used centuries ago. High quality
optical glass and multi-coatings provide modern day sky watchers views Galileo never dreamed of, making this type
of telescope popular with people who want mechanical simplicity, rugged reliability and ease of use. Because the
focal length is limited by the length of the tube, refractor telescopes become quite bulky and expensive beyond a
four-inch aperture. This limits the light gathering properties of refractor telescopes, but it is an excellent choice for
beginners and people who prize simple operation and versatility. Refractor telescopes are a popular choice because
of their unobstructed view, high contrast and good definition.
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Equatorial Advantages
– Best for long exposure photography.
– Easy to use visually because only one axis movement
compensates for Earth’s rotation.
– Setting circles on non-computerized models help
locate astronomical objects.
1
Equatorial Disadvantages
– Setup is more involved because of polar alignment
requirements.
– Not suitable for terrestrial use.
Advantages:
– Easy to use and reliable due to the simplicity of design.
– Little or no maintenance.
– Excellent for lunar, planetary and binary star observing especially in larger apertures.
– Good for terrestrial viewing.
– High contrast images with no secondary mirror or diagonal obstruction.
– Color correction is good in achromatic designs and excellent in apochromatic and fluorite designs.
– Sealed optical tube reduces image-degrading air currents and protects optics.
– Objective lens is permanently mounted and aligned.
Do you want GoTo computer automation?
Many Celestron telescopes include a GoTo computer.
GoTo capability is very useful for the beginner who
needs help in finding objects in the sky. The computer
also contains a database of celestial objects making it
unnecessary to refer to star charts to identify objects to
look at. GoTo equipped Celestrons include altazimuth
and equatorial models. Even without GoTo, many
Celestron equatorial scopes have manual setting circles
that allow you to find objects in the sky with the help of
a good star map.
Do you want to use your telescope for daytime
(terrestrial) viewing?
If you do, then select a Celestron telescope mounted on
an altazimuth mount. Altazimuth mounted telescopes
6
Example of a refractor
Disadvantages
– More expensive per inch of aperture than Newtonians or catadioptrics.
– Heavier, longer and bulkier than equivalent aperture Newtonians and catadioptrics.
– The cost and size factors limit the practical maximum size primary to smaller apertures.
– Some color aberration in achromatic designs (doublet).
Example of a fork mounted telescope equatorially aligned on a wedge.
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Telescope Basics
Newtonian Reflector telescopes replace heavy lenses with mirrors to collect and focus the light, providing much
more light gathering power for the money. Because the light path is intercepted and reflected out to the side, you
can have focal lengths up to 1000mm and still enjoy a telescope that is relatively compact and portable.
A Newtonian Reflector telescope offers such impressive light gathering characteristics you can take a serious interest
in deep space astronomy even on a modest budget. Newtonian Reflector telescopes do require more care and
maintenance because the primary mirror is exposed to air and dust. However, this small drawback does not hamper
this type of telescope’s popularity with those who want an economical telescope that can still resolve faint, distant
objects.
Newtonian reflectors produce a right-side-up image but the image will appear rotated based on the location of the
eyepiece holder in relation to the ground. Newtonian reflectors are best for astronomical use where right-side-up
does not matter.
Disadvantages
– Generally not suited for terrestrial applications.
– Slight light loss due to secondary (diagonal) obstruction when compared with refractors.
Celestron Newtonian Telescopes
Firstscope Tabletop 76 Newtonian Reflector on an Altazimuth Mount (#31034)
Firstscope 76 EQ Newtonian Reflector on a German Equatorial Mount (#31032)
Firstscope 114 EQ Newtonian Reflector on a German Equatorial Mount (#31044)
Firstscope 114 EQ Short Newtonian Reflector on a German Equatorial Mount (#31041)
C6-N Newtonian Reflector on a CG-4 German Equatorial Mount (#31056)
C8-N Newtonian Reflector on a CG-5 German Equatorial Mount (#31061, #31062)
C10-N Newtonian Reflector on a CG-5 German Equatorial Mount (#11047, #11048)
NexStar 114GT Computerized GoTo Newtonian Reflector Telescope (#31142)
2
Newtonian Reflector
A Newtonian reflector uses a single concave mirror as its primary. Light enters the tube traveling to the mirror at the
back end. There light is bent forward in the tube to a single point, its focal point. Since putting your head in front of
the telescope to look at the image with an eyepiece would keep the reflector from working, a flat mirror called a
diagonal intercepts the light and points it out the side of the tube at right angles to the tube. The eyepiece is placed
there for easy viewing.
Advantages
– Lowest cost per inch of aperture compared to refractors and catadioptrics since mirrors can be produced at less
cost than lenses in medium to large apertures.
– Reasonably compact and portable up to focal lengths of 1000mm.
– Excellent for faint deep sky objects such as remote galaxies, nebulae and star clusters due to the generally fast
focal rations (f/4 to f/8).
– Reasonably good for lunar and planetary work.
– Good for deep sky astrophotography (but not as convenient and more difficult to use than catadioptrics).
– Free of color aberration due to the use of a primary mirror.
1
Celestron Refractor Telescopes
Firstscope 60 AZ Refractor on an Altazimuth Mount (#21052)
Firstscope 60 EQ Refractor on a German Equatorial Mount (#21067)
C4-R Refractor on a CG-4 German Equatorial Mount (#21016)
C6-R Refractor on a CG-5 German Equatorial Mount (#21019, #21020)
NexStar 60GT Computerized GoTo Refractor Telescope (#22062)
NexStar 80GT Computerized GoTo Refractor Telescope (#22082)
Catadioptric Telescopes
Catadioptrics use a combination of mirrors and lenses to fold (reflect) the light path and form an image. There are
two popular designs: the Schmidt-Cassegrain and the Maksutov-Cassegrain. In the Schmidt-Cassegrain the light
enters through a thin aspheric Schmidt correcting lens, then strikes the spherical primary mirror and is reflected
back up the tube and intercepted by a small secondary mirror which reflects the light out an opening in the rear of
the instrument where the image is formed at the eyepiece. Catadioptrics are the most popular type of instrument,
with the most modern design, marketed throughout the world in 5” and larger apertures.
3
Catadioptric telescopes combine the practical advantages of lenses and mirrors while canceling their disadvantages.
They offer the clarity and contrast of refractors with the low aberrations of reflectors, all with an average focal ratio
of f/10, wide enough for all types of photography. They are also easier to maintain with all optical elements solidly
mounted and rigidly collimated. Catadioptric telescopes provide the best possible combination of light gathering
power, long focal length, portability and affordability.
Catadioptric reflectors make good terrestrial spotting scopes as well as excellent astronomical ones.
4
Example of a Newtonian telescope
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Telescope Basics
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Diagram of a Schmidt-Cassegrain optical system
Schmidt-Cassegrain Advantages
– Best all-purpose telescope design. Combines the optical advantages of both lenses and mirrors
while canceling their disadvantages.
– Excellent optics and razor sharp images over a wide field.
– Excellent for deep sky observing and astrophotography.
– Very good for lunar, planetary and binary star observing.
– Excellent for terrestrial viewing and photography.
– Focal ratio generally around f/10. Useful for all types of photography. For faster astrophotography,
use a Reducer/Corrector lens.
– Closed tube design reduces image-degrading air currents.
– Extremely compact and portable.
– Easy to use.
– Durable and virtually maintenance free.
– Large apertures at reasonable cost and less expensive than equivalent aperture refractors.
– Most versatile type of telescope.
– More accessories available than with other types of telescopes.
– Best near focus capability of any type of telescope.
1
Schmidt-Cassegrain Disadvantages
– More expensive than Newtonians of equal aperture.
– Slight light loss due to secondary mirror obstruction compared to refractors.
8
Celestron Schmidt-Cassegrain Telescopes
C5-S Schmidt-Cassegrain Telescopes on a CG-5 German Equatorial Mount (#11071, #11072)
C8-S Schmidt-Cassegrain Reflectors on a CG-5 German Equatorial Mount (#11025, #11026)
C91/4-S Schmidt-Cassegrain Reflectors on a CG-5 German Equatorial Mount (#11045, #11046)
NexStar 5i and 8i Computerized GoTo Schmidt-Cassegrain Telescope (#11033, #11021)
NexStar 8GPS, 91/4GPS and 11GPS Schmidt-Cassegrain Telescopes (#11052, 11056, #11053)
CGE 800 Schmidt-Cassegrain Reflector on a German Equatorial Mount (#11058)
CGE 925 Schmidt-Cassegrain Reflector on a German Equatorial Mount (# 11059)
Diagram of a Maksutov-Cassegrain optical system
The Maksutov-Cassegrain is similar to the Schmidt-Cassegrain with basically the same advantages and
disadvantages. It uses a thick meniscus correcting lens with a strong curvature
and a secondary mirror that is usually an aluminized spot on the corrector. The Maksutov secondary mirror is
typically smaller than the Schmidt’s giving it slightly better resolution for planetary observing.
Advantages (over Schmidt-Cassegrain)
– Smaller secondary obstruction offers a slight increase in planetary detail and contrast.
– Easier to make, resulting in lower costs.
– Longer focal lengths resulting in higher magnifications for planetary viewing.
Disadvantages (over Schmidt-Cassegrain)
– Heavier because of the thick meniscus correcting lens.
– Longer time to reach thermal stability in larger apertures over 90mm.
– Longer focal lengths resulting in smaller field of views.
Celestron Maksutov-Cassegrain Telescopes
NexStar 4GT Computerized GoTo Maksutov-Cassegrain Telescope (#11041)
T
he Celestron Firstscope Series of telescopes is designed with
the first-time telescope buyer in mind. Offering exceptional
value, these scopes feature compact and portable designs with
ample optical performance to excite any newcomer to the
world of amateur astronomy. Each telescope has its own design
characteristics to help you choose which is best for you. The
smaller Firstscopes feature refractor optical designs while the
larger apertures feature Newtonian reflector optical systems.
Every instrument features all glass (not plastic) optical elements
as well as smooth operating aluminum tripod mountings
featuring slow motion controls on most models. Refractor
models feature coated optics for enhanced image brightness
and clarity. There are models that use altazimuth mountings
that work well for terrestrial as well as astronomical viewing.
Equatorial models are intended for astronomical use only.
Adding a motor drive that moves one axis to compensate for
the Earth’s rotation can enhance equatorial mounts. When
properly aligned, the motor keeps objects in the field of view
for longer periods without having to move the telescope by
hand. Alignment also improves the accuracy of the setting
circles. Setting Circles are used to locate objects by means of
coordinates found in optional star charts.
Every instrument features Celestron’s award winning quality
and design features.
FIRSTSCOPE 60AZ
FIRSTSCOPE 60EQ
Which Firstscope model fits your needs best?
If you want a dual-purpose telescope appropriate for both
terrestrial and celestial viewing, then the refractor models are
for you. Refractors produce bright, clear images of the moon
and planets as well. It is easy to see the moons of Jupiter and
the rings of Saturn with every one of these fine instruments.
For better views of the brighter deep space objects like galaxies
and nebulae, then the larger aperture and light gathering
ability of the Newtonian reflectors are a better choice. If your
interest is strictly being able to watch for whales or spot birds,
then the altazimuth mounting versions are best. If you just
want to look at the stars, nebulae, star clusters and planets,
then the German Equatorial mounts are a better choice.
When used for astronomical viewing, these telescopes yield
breathtaking views of the Moon, Saturn with its ring structure,
Jupiter and its belts and moons, nebulae and star clusters. Add
an optional solar filter, and you can observe activity on the sun.
For more information about Celestron’s telescope mounting
choices, look at the section titled Telescope Basics.
FIRSTSCOPE 70EQ
FIRSTSCOPE 80AZ
FIRSTSCOPE 80EQ
FIRSTSCOPE 102AZ
FIRSTSCOPE 76 TABLETOP
FIRSTSCOPE 76EQ
FIRSTSCOPE 114EQ
FIRSTSCOPE 114EQ SHORT
FIRSTSCOPE
TELESCOPES
Object: Moon
Instrument: FS 60AZ
Photographer: Klaus Modinger
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(#21052)
Firstscope 60 EQ Refractor
(#21067)
(#21076)
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Firstscope 60 AZ Refractor
60 AZ STANDARD ACCESSORIES INCLUDE:
60 EQ STANDARD ACCESSORIES INCLUDE:
1-1/4" 20mm (35x), 10mm (70x) Eyepieces
90° Star Diagonal – 1-1/4"
StarPointer Finderscope
Altazimuth Mount
The Sky L1 CD ROM
1.5x Erect Image Eyepiece
Equatorial Mount
The Sky L1 CD ROM
Equatorial Mount
The Sky L1 CD ROM
SPECIFICATIONS:
SPECIFICATIONS:
SPECIFICATIONS:
60mm (2.4") Refractor
700mm Focal Length, f/12
Slow Motion Control Rod for smooth vertical adjustments
Sturdy Adjustable Aluminum Tripod with Accessory Tray
Telescope Weight: 7 lb.
Equatorial Mount with Setting Circles and Slow Motion Adjustment Cables
1
RECOMMENDED ACCESSORIES:
10
Quality and economy coupled with exceptional portability
combine in these ideal first telescopes. Sturdy, smoothoperating mounts make finding things easier and quicker.
The German Equatorial “EQ” has slow-motion controls to
aid in following celestial views while the altazimuth “AZ”
also makes a great terrestrial spotting scope. Both are
excellent for looking at the moon and planets. These
telescopes all have coated glass optics and glossy black
aluminum tubes.
Description
Filters
Eyepiece Filter Set – 1-1/4"
(21, 80A, ND-13, Polarizing)
(12, 25, 56, ND-25)
LPR Filter for 1-1/4" Eyepieces
Moon Filter for 1-1/4" Eyepieces
Solar Filter (60mm)
Solar Filter (70mm)
Item #
94119-10
94119-20
94126-A
94119-A
94131
94135
Description
General Accessories
Telescope Case – Soft Durable Nylon
Tripod Case – Soft Durable Nylon
General Accessories(cont.)
Flashlight – Night Vision
Sky Maps
Motor Drive
Motor Drive – Single Axis RA (60EQ Only)
Item #
302160
302057
93588
93722
93510
Description
Optical Accessories
Barlow Lens, 2X 1-1/4" OMNI
Diagonal – Erect Image (45º, 1-1/4")
Eyepiece – OMNI Plössl – 15mm
Photo Accessories
T-Adapter – Universal (1-1/4")
Item #
93326
94112-A
93320
93318
93625
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(#21083)
(#21086)
(#21013)
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45º Erect Image Diagonal – 1-1/4"
Altazimuth Mount
The Sky L1 CD ROM
90º Star Diagonal – 1-1/4"
Equatorial Mount
The Sky L1 CD ROM
1-1/4" 20mm Plössl (25x) Eyepiece
45º Erect Image Diagonal – 1-1/4"
6x30 Finderscope
Altazimuth Mount
The Sky L1 CD ROM
SPECIFICATIONS:
SPECIFICATIONS:
Specifications:
SPECIFICATIONS:
Slow Motion Adjustment Cables
Slow Motion Adjustment Cables
Telescope Weight: 17.5 lb.
3
The equatorial mount of the 80EQ is larger and more
rugged than the ones supplied with the Firstscope 60’s and
is complete with setting circles, latitude scale and slow
motion controls on both axes. The tripod is also larger and
more rugged than that offered on the 60mm sizes or on
most competitive 80mm models. Fitted with the optional
single axis motor drives, it will track reliably for hours.
Besides deep space objects, these instruments also offer
impressive views of the planets and the moon. The
oversized mounting and tripod on the 102AZ gives stable,
rock solid viewing.
Item #
94115-A
94119-10
94119-20
94126-A
94119-A
94135
94138
Description
General Accessories
Sky Maps
Motor Drive
Motor Drive – RA with Hand Control (80EQ Only)
Optical Accessories
Barlow Lens – 2 x 1-1/4" OMNI
Diagonal – Erect Image (45º, 1-1/4", 80EQ Only)
Photo Accessories
Item #
93588
93722
93515
4
Quality, economy and exceptional portability are combined
in these ideal first telescopes. Sturdy, smooth-operating
mounts make finding things easier and quicker. The
German Equatorial “EQ” has slow-motion controls to aid
in following celestial views while the altazimuth “AZ” is
better for looking at things terrestrially. Both are excellent
for looking at the moon and planets. The Firstscope 80’s
have 131 times the light gathering ability of the unaided
eye and 78% brighter images than those produced by
a 60mm refractor telescope, making these telescopes
an excellent choice for the serious beginning astronomer
or terrestrial observer.
Description
Diagonals
Star Diagonal – 1-1/4"
Filters
(12, 25, 56, ND-25)
Solar Filter (FS80)
Solar Filter (FS102)
93326
94112-A
93320
93323
93625
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Firstscope 76 EQ Newtonian Reflector
(#31034)
(#31032)
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4
Firstscope 76 Tabletop Newtonian Reflector
The Firstscope 76 EQ uses a German Equatorial mount
with setting circles and slow motion controls on both the
right ascension (RA) and declination (DEC) axes. These
features make it easier to locate and track objects.
76 TABLETOP STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
SPECIFICATIONS:
.96" – 20mm (30x), 4mm (150x) Eyepieces, 2x Barlow Lens
5x24 right angle Finderscope
Altazimuth Mount
The Sky L1 CD ROM
76mm (3") reflector
Altazimuth Tabletop Mount
Equatorial Mount
The Sky L1 CD ROM
76mm (3") reflector
Equatorial Mount with Setting Circles and Slow Motion
Adjustment Cables
2
The Firstscope 76 Tabletop is an ultra-portable telescope,
ideal for traveling or for setting up quickly anywhere.
A handy-but-sturdy table tripod mount provides steady
viewing. This telescope is small but powerful so you can
study Saturn and its rings, Jupiter and its surface details
and moons and many deep-sky objects including galaxies,
nebulae and star clusters.
1
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Description
Recommended for Tabletop 76:
General Accessories
Sky Maps
Optical Accessories
Item #
93588
93722
93326
Description
Recommended for Tabletop 76EQ:
Filters
(12, 25, 56, ND-25)
Item #
94119-10
94119-20
Description
Filters (cont.)
Solar Filter (FS 76EQ)
General Accessories
Sky Maps
Item #
94126-A
94119-A
94133
93588
93722
Description
Optical Accessories
Barlow Lens – 2X 1-1/4" OMNI
Photo Accessories
Item #
93326
93320
93322
93625
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Firstscope 114 EQ Newtonian Reflector
Firstscope 114 EQ Short Newtonian Reflector
(#31044)
(#31041)
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The short version of the 114mm Newtonian telescope offers
more portability than the standard longer tube Newtonian
without sacrificing power or performance. The short tube
of this model is only 18” long and has a built-in correction
lens, giving it all the focal length of the standard model,
while reducing aberrations. The equatorial mount is quite
stable, with setting circles and slow motion controls on
both axes for easy, smooth tracking.
The Firstscope 114 series features two models to meet your
individual needs. The Firstscope 114 EQ is an economical
telescope with a superb optical system housed in a glossy
black metal tube. The CG-3 equatorial mount is quite stable,
with setting circles and slow motion controls on both axes
for easy, smooth tracking. Strict adherence to Celestron’s
tough quality standards for manufacturing, assembly and
testing ensures that each telescope performs well.
SPECIFICATIONS:
114 EQ SHORT STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
Equatorial Mount
The Sky L1 CD ROM
114mm (4.5") Reflector
CG-3 Equatorial Mount with Setting Circles and Slow Motion
Adjustment Cables
Equatorial Mount
The Sky L1 CD ROM
114mm (4.5") Reflector
CG-2 Equatorial Mount with Setting Circles and Slow Motion
Adjustment Cables
Description
Filters (cont.)
Solar Filter
Description
General Accessories
Case – Hard (FS 114 Short)
Sky Maps
4
Description
Filters
(12, 25, 56, ND-25)
Item #
94119-10
94119-20
Item #
94126-A
94119-A
94134
Item #
302114
93588
93722
Description
Optical Accessories
Photo Accessories
Item #
93326
93320
93322
93625
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3
SPECIFICATIONS
4
FIRSTSCOPES
Optical Design
Focal Length
Finderscope
Mount
Eyepiece
Eyepiece
Star Diagonal / Erect Image Eyepiece
Accessory tray
Tripod
CD ROM
Highest Useful Magnification
Limiting Stellar Magnitude
Resolution: Rayleigh
Dawes Limit
Photographic Resolution
Field of View: standard eyepiece
Linear FOV (@1000 yd.)
Secondary Mirror Obstruction
Optical Coatings
Optical Tube Length
Telescope Weight
SPECIFICATIONS
2
FIRSTSCOPES
Optical Design
Focal Length
Finderscope
Mount
Eyepiece
Eyepiece
Star Diagonal / Erect Image Eyepiece
Accessory tray
Tripod
CD ROM
TECHNICAL SPECS
RECOMMENDED ACCESSORIES
1
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Firstscopes – Standard Equipment and Specifications
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Dawes Limit
Linear FOV (@1,000 yd.)
Optical Coatings
Optical tube length
Telescope Weight
21052
Firstscope 60 AZ
21067
Firstscope 60 EQ
21076
Firstscope 70 EQ
31032
Firstscope 76 EQ
31034
Firstscope 76 Tabletop
60mm (2.4") refractor
700mm f/12
StarPointer
Altazimuth
1-1/4" – 20mm (35x)
1-1/4" – 10mm (70x)
1-1/4"/1.5x E.I. Eyepiece
yes
Aluminum
The Sky L1
900mm f/15
StarPointer
Equatorial
1-1/4" – 20mm (45x)
1-1/4" – 10mm (90x)
1-1/4" 90º
yes
Aluminum
The Sky L1
900mm f/13
StarPointer
Equatorial
1-1/4" – 20m (45x)
1-1/4" – 10mm (90x)
1-1/4" 90º
yes
Aluminum
The Sky L1
76mm (3") reflector
700mm f/9
StarPointer
Equatorial
1-1/4" – 20mm (35x)
1-1/4" – 10mm (70x)
n/a
yes
Aluminum
The Sky L1
SPECIFICATIONS:
76mm (3") reflector
600mm f/8
5x24 right angle
Altazimuth Tabletop
.96" – 20mm H (30x)
.96" – 4mm H (150x)
n/a
n/a
Tabletop
The Sky L 1
142x
11.4
2.31 arcseconds
1.93 arcseconds
156 lines/mm
73x unaided eye
1.4º
75 ft.
n/a
Fully-Coated
28"
7 lb.
142x
11.4
2.31 arcseconds
1.93 arcseconds
121 lines/mm
73x unaided eye
1.1º
58 ft.
n/a
Fully-Coated
28"
11 lb.
165x
11.7
1.98 arcseconds
1.66 arcseconds
141 lines/mm
100x unaided eye
1.1º
58 ft.
n/a
Fully-Coated
30"
17 lb.
180x
11.9
1.82 arcseconds
1.53 arcseconds
217 lines/mm
118x unaided eye
1.4º
75 ft.
1.2" (40% by diameter, 16% by area)
Aluminum
27"
15 lb.
180x
11.9
1.82 arcseconds
1.53 arcseconds
250 lines/mm
118x unaided eye
1.7º
87.5 ft.
Aluminum
11"
4 lb.
21083
Firstscope 80 AZ
21086
Firstscope 80 EQ
21013
Firstscope 102 AZ
31041
Firstscope 114 EQ Short
31044
Firstscope 114 EQ
900mm f/11
StarPointer
Altazimuth
1-1/4" – 20m (45x)
1-1/4" – 10mm (90x)
1-1/4" 45º Erect Image
yes
Aluminum
The Sky L1
900mm f/11
StarPointer
Equatorial
1-1/4" – 20m (45x)
1-1/4" – 10mm (90x)
1-1/4" 90º
yes
Aluminum
The Sky L1
500mm f/5
6x30
Altazimuth
1-1/4" – 20mm (25x)
n/a
1-1/4" 45º Erect Image
yes
Aluminum
The Sky L1
114mm (4.5") reflector
1000mm f/9
StarPointer
Equatorial
1-1/4" – 20mm (50x)
1-1/4" – 10mm (100x)
n/a
yes
Aluminum
The Sky L1
900mm f/8
StarPointer
Equatorial
1-1/4" – 20mm (45x)
1-1/4" – 10mm (90x)
n/a
yes
Aluminum
The Sky L1
189x
12
1.73 arcseconds
1.45 arcseconds
162 lines/mm
131x unaided eye
1.2º
61 ft.
n/a
Multi-Coated
36"
18 lb.
241x
12.5
1.36 arcseconds
1.14 arcseconds
371 lines/mm
212x unaided eye
2º
105 ft.
n/a
Multi-Coated
21"
17.5 lb.
269x
12.8
1.21 arcseconds
1.02 arcseconds
228 lines/mm
265x unaided eye
1º
52.5 ft.
Aluminum
19"
16 lb.
269x
12.8
1.21 arcseconds
1.02 arcseconds
250 lines/mm
265x unaided eye
1.2º
60 ft.
Aluminum
35"
19 lb.
DESCRIPTIONS
189x
12
1.73 arcseconds
1.45 arcseconds
162 lines/mm
131x unaided eye
1.2º
61 ft.
n/a
Multi-Coated
36"
18 lb.
All specifications are subject to change without notice or obligation.
T
ADVANCED GT
DATABASE
Complete
Revised
NGC
Catalog
7,840
Complete
Messier
Catalog
110
Complete IC
Catalog
5,386
Complete
Caldwell
Abell
Galaxies
Solar System
objects
Famous
Asterisms
Selected CCD
Imaging
Objects
109
2,712
9
20
25
Selected SAO
Stars
29,500
Total Object
Database 45,492
he Celestron Advanced Series of telescopes offers additional
features, heavier mountings and larger apertures. These
exceptional instruments are designed for the person who wants
to step up to a larger aperture telescope to gain extra light
gathering power. They also make excellent first telescopes for
those who wish to start with a more capable instrument. The
Advanced Series comes on German Equatorial mounts for
additional stability and accessory use. The GT versions of the
Advanced Series are available on a computerized GoTo version
of Celestron’s respected CG-5 mount, which includes the
NexStar computer control system. The CG-5 mount now
includes ultra sturdy 2” stainless steel legs for extra rigidity and
vibration dampening. The Advanced Series come with your
choice of refractor, reflector and Schmidt-Cassegrain models.
The refractor models range from a 4” to an impressive 6”
aperture. For even more light gathering power there are 6”, 8”
and 10” Newtonian Reflector models and three models
featuring Schmidt-Cassegrain optical designs with 5”, 8” and
9 1/4” apertures. All models meet Celestron’s uncompromising
standards of optical excellence. The C6-R, C8-N and C10-N also
include a smooth and sturdy 2” focuser that allows you
to move up to 2” eyepieces and carry heavier accessory loads.
If you’re buying your first telescope, or upgrading from a
smaller model, the Celestron Advanced Series offers improved
performance, more stable mountings and exciting add-on
options that make astrophotography possible. When used for
astronomical viewing, these telescopes yield breathtaking views
of the Moon, Saturn with its ring structure, Jupiter and its belts
and moons, nebulae and star clusters.
Advanced Series CG-5GT Computerized German Equatorial
Mount (#91518)
Object: M20
Instrument: C 91/4
Photographer: Rich Jacob
The CG-5 GT computerized mount is also provided separately to
give full automated GoTo capability to your favorite telescope
tube assembly. This German Equatorial mount has precision
worm gears on both axes for extremely smooth tracking and
C4-R
C6-N
slewing. The CG-5 uses large shafts and bearings and more
substantial base castings for additional stability. The tripod on
the CG-5 has larger, stronger legs with excellent damping
characteristics for more stable views. The CG-5 also has a
convenient latitude scale for easier alignment and an optional
polar alignment scope for the ultimate in precision orientation.
Couple this solid mount with the included computerized
control system to access many of the same functions and
features as Celestron’s most advanced GoTo telescopes. Capable
o
of holding over 35 lb. of payload and slewing 5 per second you
will be able to instantly point to any of the celestial objects in
its 40,000 object database.
C5-S
C5-SGT
C6-R
C6-RGT
The CG-5 GT also includes these high performance features:
• Double line, 16 character Liquid Crystal Display Hand Control
with 19 fiber optic backlit LED buttons
• DC Servo motors with encoders on both axes
• RS-232 communication port on hand control; Auxiliary Port
and Autoguider Port on motor drive
• 40,000+ object database with 400 user-definable objects and
expanded information on over 200 objects, plus
• Custom database lists of all the most famous deep-sky
objects by name and catalog number; the most beautiful
double, triple and quadruple stars; variable stars, solar system
objects and asterisms
ADVANCED
C8-S
C8-SGT
C 91/4-S
C 91/4-SGT
C8-N
C8-NGT
C10-N
C10-NGT
TELESCOPES
15
A
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PAG E NU M B ER
1
Advanced Series C6-N Newtonian Reflector
(#21016)
(#31056)
3
4
Advanced Series C4-R Refractor
The C6-N uses a diffraction-limited parabolic primary
mirror for razor sharp star images across a wide field of
view. The optics of this heavy-duty telescope are
manufactured to Celestron ‘s uncompromising standards
with star images that are classic textbook Airy disks.
C4-R STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
C6-N STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
1-1/4" 20mm Eyepiece (50x)
6x30 Finderscope and Mounting Bracket
CG-4 Equatorial Mount and Tripod
Rack and Pinion Focuser – 1-1/4"
90° Mirror Diagonal – 1-1/4"
The Sky Level I CD-ROM
Accessory Tray
102mm (4.0") Refractor Optical Design
1000mm f/10 Focal Length
Sturdy, Adjustable Aluminum Tripod with Accessory Tray
Rack and Pinion Focuser - 1-1/4"
Accessory Tray
150mm (6.0") Reflector Optical Design
Description
Filters (cont.)
General Accessories
Sky Maps
Description
General Accessories (cont.)
Motor Drive – SA with Hand Control
Motor Drive – DA with Hand Control
Optical Accessories
Eyepiece – Axiom 1-1/4" – 15mm
1
2
These telescopes are carefully designed for the more
advanced astronomer and feature exquisite optics on
a heavy-duty mount. The optics of this telescope are
made to exacting standards, with high quality materials
to ensure top performance. The C4-R offers a 63%
increase in image brightness over 80mm models, with
the larger aperture delivering incredible images of the
Moon; Saturn and its ring structure; Jupiter and its belts;
and hundreds of deep-sky objects, including galaxies,
nebulae and star clusters.
Description
Filters
(12, 25, 56, ND-25)
16
Both Telescopes are mounted on the CG-4 mount. The
mount features precision gears for extremely smooth motion.
A counterweight, latitude scale, setting circles, and slow
motion controls on both axes are standard, so you have a
fully loaded telescope right from the start.
Item #
94119-10
94119-20
Item #
94126-A
94119-A
93588
93722
Item #
93517
93522
93326
93357
Description
Optical Accessories (cont.)
Eyepiece – Axiom 2" – 19mm
Item #
93362
93359
93365
A
C
B
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PA G E NU MBE R
1
Advanced Series C5-S Schmidt-Cassegrain
Advanced Series C5-SGT Schmidt-Cassegrain
(#11071)
(#11072)
1
2
For a completely automated GoTo system, the C5-SGT
(#11072) comes mounted on the CG-5GT computerized EQ
mount and allows access to features like automatic star
alignment capability and GoTo slewing to over 40,000
objects. Equipped with high-speed motors and hand
control, the C5-SGT allows you to remotely slew your
telescope to desired objects quickly and accurately. No
matter at what level you are starting out, the Advanced
GT series will unfold all the wonders of the universe for
you and your friends .
C5-S STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
C5-SGT STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
Accessory Tray
127mm (5.0") Schmidt-Cassegrain Optical Design
Adjustable 2" Steel Leg Tripod with Accessory Tray/Leg Brace
Right Ascension and Declination Setting Circles
Slow Motion Control Knobs on Both Axes
Accessory Tray
40,000+ objects, 400 user defined programmable objects.
Enhanced information on over 200 objects
Double line, 16 character Liquid Crystal Display; Hand Control
DC Servo Motors with Encoders on both Axes
4º/second Max. Slew Speed
RS-232 communication port on hand control
Auxiliary Port and Autoguider Port on motor drive
Description
Filters (cont.)
General Accessories
Sky Maps
Description
Optical Accessories
3
A serious, high performance telescope in a compact size,
The 5" aperture of the C5-S allows it to easily outperform
smaller aperture telescopes. Offering 4-1/2 times more
light gathering ability than a 60mm telescope and 2-1/2
times more than an 80mm scope, Celestron’s C5-S is the
clear choice when a powerful instrument delivering brilliant,
crisp views is what you require. The reputation for
excellence of this optical system is such that it was chosen
by NASA for many space shuttle missions. On or off the
sturdy CG-5 Equatorial mount, the C5-S makes a
wonderful spotting scope and a powerful telephoto lens.
4
Description
Filters
(12, 25, 56, ND-25)
Item #
94119-10
94119-20
Item #
94126-A
94119-A
Item #
93326
93357
93362
Description
Item #
93359
93365
93588
93722
17
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1
Advanced Series C6-RGT Refractor
(#21019)
(#21020)
1
2
3
4
Advanced Series C6-R Refractor
C6-R STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
C6-RGT STANDARD ACCESSORIES INCLUDE:
COMPUTER SPECIFICATIONS:
Accessory Tray
150mm (6.0") Refractor Optical Design
Accessory Tray
40,000+ objects, 400 user defined programmable objects
Description
Filters (cont.)
General Accessories
Sky Maps
Description
Motor Drive-SA with Hand Control
Motor Drive-DA with Hand Control
Optical Accessories
Description
Filters
(12, 25, 56, ND-25)
18
For a completely automated GoTo system, the C6-RGT
(#21020) comes mounted on the CG-5GT computerized
EQ mount and allows access to features like automatic
star alignment capability and GoTo slewing to over
40,000 objects. Equipped with high-speed motors and
hand control, the C6-RGT allows you to remotely slew
your telescope to desired objects quickly and accurately.
No matter at what level you are starting out, the
Advanced GT series will unfold all the wonders of the
universe for you and your friends .
This deluxe quality 1200mm focal length, f/8 German
Equatorial mounted achromatic refractor is an incredible
value. An excellent choice for the serious astronomer, the
C6-R is the largest telescope in its class with over 6 times
the light gathering ability of a 60mm. This telescope
offers outstanding light gathering capability and stability.
It features premium accessories such as a heavy duty
CG-5 German equatorial mount, 9x50 finderscope with
bi-directional alignment screws and a spring loaded pivot
support, 20mm Plössl 1-1/4" eyepiece, 2" focuser, 2x
Barlow with photo adapter, adjustable aluminum tripod
and much more.
Item #
94119-10
94119-20
Item #
94126-A
94119-A
93588
93722
Item #
93518
93523
93326
93357
Description
Item #
93362
93359
93365
A
C
B
D
PAG E NU MBE R
1
Advanced Series C8-S Schmidt-Cassegrain Reflector
(#11025)
Advanced Series C8-SGT Schmidt-Cassegrain Reflector
(#11026)
1
For a completely automated GoTo system, the C8-SGT
(#11026) comes mounted on the CG-5 GT computerized
EQ mount and allows access to features like automatic star
objects. Equipped with high speed motors and hand
control, the C8-SGT allows you to remotely slew your
matter at what level you are starting out, this precision
instrument will satisfy your needs both visually and
photographically.
C8-S STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
C8-SGT STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
1-1/4" 25mm Plössl Eyepiece (81x)
Accessory Tray
203mm (8.0") Schmidt-Cassegrain Optical Design
2,032mm f/10 Focal Length
Accessory Tray
40,000+ objects, 400 user defined programmable objects
Description
General Accessories
Lens Shade – Soft
Sky Maps
Optical Accessories
Diagonal – Mirror 2"
Description
Stereo Binocular Viewer
Motor Drive
2
If you’re looking for an advanced telescope with a
traditional German Equatorial mount or want to upgrade
to a larger aperture telescope, consider the C8-S telescope.
Mounted on the CG-5 EQ mount, both axes have precision
worm gears for extremely smooth motion. Equipped with
2" steel legs, this heavy duty mount delivers jitter-free
images. With adjustable height, the very rigid tripod has
excellent damping characteristics and a convenient
accessory tray/leg brace for added strength. Included are
setting circles on both axes, slow-motion controls and
latitude scale. An adjustable counterweight makes it easy
to point, balance and use. The C8-S optical system comes
with StarBright coatings and its large aperture offers light
gathering power 843 times that of the human eye. An
optional polar alignment scope for quick alignment as
well as a motor drive is available for easy tracking for all
CG-5 mounted telescopes.
3
Item #
94119-10
94119-20
94126-A
94127-A
94119-A
Item #
94012
93588
93722
93326
94112-A
93519
Item #
93690
93357
93362
93359
93365
Description
Photo Accessories
Focus Motor
Microguide Eyepiece
Piggyback Adapter
Radial Guider
Reducer Corrector f/6.3
T-Adapter – SCT
Item #
94142
94171
93598
94176
94175
93633-A
4
Description
Filters
(12, 25, 56, ND-25)
LPR Filter for Back Threads of SCT’s
93518
93523
19
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1
(#11045)
Advanced Series C91/4-SGT Schmidt-Cassegrain Reflector
(#11046)
3
4
Advanced Series C91/4-S Schmidt-Cassegrain Reflector
For a completely automated GoTo system, the C91/4-SGT
EQ mount and allows access to features like automatic
star alignment capability and GoTo slewing to over
40,000 objects. Equipped with high speed motors and
hand control, the C91/4-SGT allows you to remotely slew
your telescope to desired objects quickly and accurately.
No matter at what level you are starting out, this
precision instrument is design to expand as your interest
in astronomy grows.
C9 1/ 4 -S STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
C9 1/ 4 -SGT STANDARD ACCESSORIES INCLUDE:
Accessory Tray
235mm (9-1/4") Schmidt-Cassegrain Optical Design
2,350mm f/10 Focal Length
Accessory Tray
Description
General Accessories
Lens Shade – Soft
Sky Maps
Optical Accessories
Description
Motor Drive
2
The C91/4-S telescope combines the unequaled optical
excellence of a Celestron 91/4” Schmidt-Cassegrain
telescope with the economical CG-5 German equatorial
mount. The C91/4-S optical tube was specifically optimized
for sharp visual and photographic use. Its longer primary
focal length and lower magnification secondary mirror
contributes to a flatter field of view and helps to further
reduce optical aberrations. The optimized baffling system
benefits astrophotography and gives high contrast views of
the planets. With 33% more light gathering than the 8"
model, the C91/4-S is compatible with the complete line of
Celestron photographic and visual accessories.
1
20
Description
Filters
(12, 25, 56, ND-25)
Item #
94119-10
94119-20
94126-A
94119-A
Item #
94013
93588
93722
93326
94112-A
93519
93690
Item #
93357
93362
93359
93365
93518
93523
Description
Photo Accessories
Microguide Eyepiece
Piggyback Adapter
Radial Guider
T-Adapter – SCT
Item #
94171
93598
94176
94175
93633-A
A
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B
D
PA G E NU MBE R
1
Advanced Series C8-NGT Newtonian Reflector
(#31061)
(#31062)
1
2
For a completely automated GoTo system, the C8-NGT
control, the C-8NGT allows you to remotely slew your
matter at what level you are starting out, the Advanced
GT series is designed to provide you with years of
observing pleasure.
SPECIFICATIONS:
C8-NGT STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
Accessory Tray
200mm (8.0") Newtonian Reflector Optical Design
1,000 mm f/5 Focal Length
2" Rack & Pinion Focuser with 1-1/4" adapter
Accessory Tray
Description
Filters (cont.)
General Accessories
Sky Maps
Description
Optical Accessories
3
The optics of the C8-N telescope are manufactured to
Celestron‘s uncompromising standards. The C8-N uses
diffraction-limited parabolic primary mirrors for razor
sharp star images across a wide field of view. These
telescopes are mounted on the very rigid CG-5 German
equatorial mount. A counterweight, latitude scale, setting
circles, and slow motion controls on both axes are
standard, so you have a fully loaded telescope right from
the start. These mounts are the most rigid and stable type
in their price range. They feature precision gears for
extremely smooth motion. The mount is supported by
heavy duty tripod with 2” steel legs for extra stability and
vibration free viewing.
Description
Filters
(12, 25, 56, ND-25)
4
Item #
94119-10
94119-20
Item #
94126-A
94119-A
93588
93722
Item #
93326
93357
93362
93359
Description
Motor Drive
Item #
93359
93365
93518
93523
21
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B
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Advanced Series C10-NGT Newtonian Reflector
(#11047)
(#11048)
1
2
3
4
SPECIFICATIONS:
C10-NGT STANDARD ACCESSORIES INCLUDE:
Accessory Tray
254mm (10.0") Newtonian Reflector Optical Design
1,200 mm f/4.7 Focal Length
2" Rack & Pinion Focuser with 1.25" adapter
Accessory Tray
Description
Filters (cont.)
General Accessories
Sky Maps
Description
Optical Accessories
Description
Filters
(12, 25, 56, ND-25)
22
For a completely automated GoTo system, the C10-NGT
control, the C10-NGT allows you to remotely slew your
matter at what level you are starting out, the Advanced GT
series will unfold for you and your friends all the wonders
of the universe.
The C10-N is the largest Newtonian in its class with 178%
more light gathering than the 6 inch model and almost
twice the resolving power. The optics of the C10-N
telescope are manufactured to Celestron‘s uncompromising
standards. The C10-N uses diffraction-limited parabolic
primary mirrors for razor sharp star images across a wide
field of view. This telescope is mounted on the very rigid
CG-5 German equatorial mount. A counterweight, latitude
scale, setting circles, and slow motion controls on both
axes are standard, so you have a fully loaded telescope
right from the start. These mounts are the most rigid and
stable type in their price range. They feature precision gears
for extremely smooth motion. The mount is supported by a
heavy duty tripod with 2" steel legs for extra stability and
vibration free viewing.
Item #
94119-10
94119-20
Item #
94126-A
94119-A
93588
93722
Item #
93326
93357
93362
93359
93365
Description
Motor Drives
Item #
93518
93523
A
B
PAG E NU MBE R
Focal Length
Finderscope
Fastar Compatible
Mount
Eyepiece
Star Diagonal
Erect Image Eyepiece/Diagonal
Accessory tray
Tripod
CD ROM
11025
C8-S
31061
C8-N
11045
C9 1/4-S
11047
C10-N
1200mm f/8
9x50
n/a
CG-5 Equatorial
1-1/4" – 20mm (60x)
1-1/4"
n/a
yes
2" Stainless Steel
The Sky L1
235mm (9.25")
Schmidt-Cassegrain
2350mm f/10
6x30
no
CG-5 Equatorial
1-1/4" – 25mm (94x)
1-1/4"
254mm (10") reflector
750mm f/5
6x30
n/a
CG-4 Equatorial
1-1/4" – 20mm (38x)
n/a
n/a
yes
aluminum
The Sky L1
203mm (8")
Schmidt-Cassegrain
2032mm f/10
6x30
no
CG-5 Equatorial
1-1/4" – 25mm (81x)
1-1/4"
n/a
yes
2" Stainless Steel
The Sky L1
1000mm f/10
6x30
n/a
CG-4 Equatorial
1-1/4" – 20mm (50x)
1-1/4"
n/a
yes
Aluminum
The Sky L1
127mm(5")
Schmidt-Cassegrain
1250mm f/10
6x30
n/a
CG-5 Equatorial
1-1/4" – 25mm (50x)
1-1/4"
n/a
yes
2" Stainless Steel
The Sky L 1
1000mm f/5
9x50
n/a
CG-5 Equatorial
1-1/4" – 20mm (50x)
n/a
n/a
yes
yes
SPECIFICATIONS:
2" Stainless Steel
2" Stainless Steel
The Sky L1
The Sky L1
1200mm f/4.7
9x50
n/a
CG-5 Equatorial
1-1/4" – 20mm (60x)
n/a
n/a
yes
2" Stainless Steel
The Sky L1
241x
15x
12.5
1.36 arcseconds
1.14 arcseconds
185 lines/mm
212x unaided eye
1º
52.5 ft
Multi-Coated
n/a
n/a
n/a
40"
36 lb.
300x
18x
13
1.1 arcseconds
.91 arcseconds
200 lines/mm
329x unaided eye
1º
52.5 ft.
StarBright Coating
1.75"
12%
35%
14"
24 lb.
354x
21x
13.4
.92 arcseconds
.77 arcseconds
400 lines/mm
459x unaided eye
1.3º
68 ft.
Aluminum
1.75"
8.5%
29%
27"
35 lb.
354x
21x
13.4
.92 arcseconds
.77 arcseconds
227 lines/mm
459x unaided eye
.83º
43.8 ft
Multi-Coated
n/a
n/a
n/a
50.5"
57 lb.
480x
29x
14
.68 arcseconds
.57 arcseconds
200 lines/mm
843x unaided eye
.64º
33.6 ft.
StarBright Coating
2.5"
10%
31%
17"
54.5 lb.
480x
29x
14
.69 arcseconds
.58 arcseconds
400 lines/mm
843 unaided eye
1º
52.5 ft.
Aluminum
2.2"
8%
28%
37"
67 lb.
555x
34x
14.4
.59 arcseconds
.49 arcseconds
200 lines/mm
1127x unaided eye
.55º
29 ft.
StarBright Coating
3.35
13%
36%
22"
62 lb.
600x
36x
14.5
.54 arcseconds
.46 arcseconds
425 lines/mm
1316 unaided eye
.83º
43.8 ft.
Aluminum
2.3
5%
23%
45"
83 lb.
11072
C5-SGT
21020
C6-RGT
11026
C8-SGT
31062
C8-NGT
11046
C91/4-SGT
11048
C10-NGT
Double line, 16 character
Crystal Display; 19 fiber
optic backlit LED buttons
DC Servo motors with
encoders, both axes
4º/second
24bit, 0.08 arcsec
calculation
RS-232 communication
port on hand control
Aux Port, Autoguide Ports
Sidereal, Solar and Lunar
EQ North & EQ South
AutoAlign, 2-Star Alignment,
Quick Align
40,000+ objects, 400 user
defined programmable
objects
encoders, both axes
4º/second
24bit, 0.08 arcsec
calculation
EQ North & EQ South
Quick Align
objects
encoders, both axes
4º/second
24bit, 0.08 arcsec
calculation
EQ North & EQ South
Quick Align
objects
encoders, both axes
4º/second
24bit, 0.08 arcsec
calculation
EQ North & EQ South
Quick Align
objects
encoders, both axes
4º/second
24bit, 0.08 arcsec
calculation
EQ North & EQ South
Quick Align
objects
encoders, both axes
4º/second
24bit, 0.08 arcsec
calculation
EQ North & EQ South
Quick Align
objects
COMPUTERIZED MODELS
Hand Control
Motor: Type
Max Slew Speed
Software Precision
Hand Control Ports
Motor Ports
Tracking Rates
Tracking Modes
Alignment Procedures
Database
4
21019
C6-R
3
31056
C6-N
2
Lowest Useful Magnification
Dawes Limit
Optical Coatings
by Area
by Diameter
Optical tube length
Telescope Weight
11071
C5-S
1
Optical Design
21016
C4-R
1
ADVANCED SCOPES
SPECIFICATIONS
D
Advanced Series – Standard Equipment and Specifications
1
TECHNICAL SPECS
C
23
NEXSTAR 60GT
T
DATABASE
SAO Stars
2,767
Galaxies
641
Open
Clusters
255
Messier
Objects
110
Nebula
89
Globular
Cluster
72
Common
Named
Objects
57
Named Binary
Star
55
Planetary
Nebula
31
Named
Variable
Star
20
Solar System
Objects
9
Total Object
Database
4,033
he NexStar GT series of telescopes shares a common heritage
in features and function. Each NexStar telescope includes
the latest state-of-the-art computerized GoTo technology,
amazingly easy-to-use features and ready-to-use components.
After the computer guides you through a simple set up, each
telescope will point itself to the object you choose from its
stored database of astronomical objects without referring
to star charts!
The NexStar 60GT is the perfect “step up” from a noncomputerized telescope, or perhaps you have decided to
make the 60GT your first telescope! This extremely portable
instrument is the perfect tool to get going with amateur
astronomy. With its pre-assembled, adjustable aluminum tripod,
the NexStar GT telescopes can be set up and ready to use in a
matter of minutes. The NexStar 4GT comes on a sturdy metal
base with three rubber-gripping feet for vibration suppression
and traction. Use the NexStar 4GT on any flat surface or with
the optional field tripod. You can see views of the lunar surface,
Venus and its phases, Mars resolved as an orange disc, Jupiter
and its 4 moons, and Saturn resolved as a disc with its rings
plainly visible. You can see the Great Nebula in Orion and
the amazingly large Andromeda Galaxy that is 2.8 million
light years away. That’s over six trillion miles! Besides being
a wonderful astronomical scope, most NexStar GT’s can be
used as a great, land-based spotting telescope as well.
To assist in the star alignment, the NexStar uses a lightweight
StarPointer Finderscope. The StarPointer is the quickest and
easiest way to point your telescope exactly to the desired
object in the sky. It’s like having a laser pointer that you can
shine directly onto the night sky. No need to worry about the
inverted images you see through traditional finders, just align
the red dot seen through the StarPointer with the desired star
in the sky. It’s that easy.
Powered by 8 AA user supplied batteries or an optional AC
adapter (#18773) these NexStar GoTo’s love to travel. Sturdy
and solid, they provide rigid low-vibration performance, with
quiet, high precision servo motors.
NEXSTAR 80GT
With the NexStar’s ergonomically designed hand control, the
user is free to remove the hand control from its holder for
remote use or leave it cradled for hands-free operation. With
a touch of a button you can select the object catalog, change
the slew speed, view fascinating information about an object,
or simply know if a desired object is visible in the sky.
The NexStar GT’s deluxe features combine with Celestron’s
uncompromising optical standards to give amateur astronomers
one of the most sophisticated and easy to use telescopes
available on the market today.
NEXSTAR 114GT
NEXSTAR 4GT
Every NexStar GT includes a version of The Sky® Level 1
Planetarium software for exploring the Universe on your PC
and printing out custom star charts of the sky. In addition, you
receive the NexStar Observer’s List (NSOL) control software.
Just connect your NexStar to your laptop or PC (with optional
RS-232 cable) for click-and-slew ability to any object in the
NexStar’s database.
NEXSTAR GT
TELESCOPES
Object: Moon
Instrument: NexStar 4
Photographer: Mario Mariani
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NexStar 60GT Computerized GoTo Refractor Telescope
(#22062)
NexStar 80GT Computerized GoTo Refractor Telescope
(#22082)
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The NexStar 80GT Refractor is the most portable version
of the NexStar Series. This short-tube telescope with a fast
f/5 optical system gives images that are bright and crisp.
The 80GT is 80% brighter than the 60mm scope. And the
80GT includes computerized GoTo technology! Because of
its wide 3.25° field of view, the NexStar 80 is optimal for
scanning large areas of the sky and for superb terrestrial
(land) viewing. You can see all of the Andromeda Galaxy!
Few telescopes can say that! A wonderful first-time
astronomical scope, the 80GT can also be used as a great,
land-based spotting telescope.
60GT STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
SPECIFICATIONS:
1-1/4" 20mm (35x), 10mm (70x), and 4mm (175x) Eyepieces
Computerized Hand Control
NSOL Control Software
60mm (2.4") diameter Refractor
700mm Focal Length
f/12 Focal Ratio
Motorized Altazimuth Mount
4,000 Object Database
Nine slew speeds: 4º /sec, 2º /sec, 1º/sec, .5 /sec, 32x, 16x, 8x, 4x, 2x
Weight: 9.5 lb.
80mm (3.1") Diameter Refractor
400mm Focal Length
f/5 Focal Ratio
Weight: 11 lb.
Description
Filters
(12, 25, 56, ND-25)
Solar Filter
General Accessories
AC Adapter
Car Battery Adapter
Case – Soft Durable Nylon
Description
Case – Tripod, Durable Nylon
Sky Maps
RS-232 Cable
Optical Accessories
Photo Accessories
3
Our most affordable NexStar telescope turns starry nights
into space odysseys. The 60mm refractors come with a
fully computerized hand control with a database of over
4,000 celestial objects. With its pre-assembled, adjustable
aluminum tripod, the NexStar 60GT can be up and ready to
use in a matter of minutes. And a StarPointer Finderscope
with a red LED makes aligning a breeze. With the NexStar
60’s you can see breathtaking views of the lunar landscape,
Venus and its phases, Mars resolved as an orange disc,
Jupiter and its 4 moons, Saturn resolved as a disc, with its
rings plainly visible at medium and high magnification.
Protect your investment with a custom soft carrying case.
Add sky maps and a flashlight to assist in learning more
about the objects stored in the NexStar hand control
database. A Barlow lens is available to increase the
magnification of your existing eyepieces. An erect image
diagonal for bird watching makes views right-side-up and
corrects left-to-right.
Item #
94119-10
94119-20
94126-A
94119-A
94135
18773
18769
302160
Item #
302057
93588
93722
93920
4
You might want to expand your magnification choices
with additional eyepieces like the OMNI Plössl eyepieces
or maximize your field of view with the 70° field of view
Axiom eyepieces. Add some eyepiece filters like a Light
Pollution Reduction (LPR) filter to minimize the effects of
city lights or a moon filter to reduce the lunar brightness.
Add a solar filter to look at sunspots or eyepiece filters to
enhance planetary contrast. You might also consider an AC
adapter or car battery adapter to complement the
included battery pack.
93326
94112-A
93320
93323
93625
25
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NexStar 114GT Computerized GoTo
Newtonian Reflector Telescope (#31142)
4
NexStar 4GT Computerized GoTo
Maksutov-Cassegrain Telescope (#11041)
Featuring high-quality Maksutov-Cassegrain optics, the
NexStar 4GT is an ideal telescope for observing and
photographing the wonders of space. Sturdy metal
construction provides an extremely stable platform, making
observation at higher magnification much easier. Plus
the Flip Mirror Control and Straight Through Photographic
Port help make short-exposure astrophotography a heavenly
experience. Computerized capabilities like Auto Align,
automatic Tour Function, an easy-to-use hand control,
and a 4,000+ object database all help make the NexStar
4GT a superstar telescope at a super affordable cost.
Mounted on a sturdy metal base, the NexStar sits securely
on any flat surface and has three rubber gripping feet for
vibration suppression and traction. Weighing only 11 lb.,
the NexStar 4 is extremely portable and can be mounted
onto the optional NexStar Tripod for use in the field.
SPECIFICATIONS:
SPECIFICATIONS:
114mm (4.5") diameter Newtonian Reflector
1000mm Focal Length
f/9 Focal Ratio
Weight: 15 lb.
Sturdy, Metal Base with Rubber Feet
Tripod optional
102mm (4.0") diameter Maksutov-Cassegrain
1325mm Focal Length
f/13 Focal Ratio
Weight: 11 lb.
Description
Filters
(12, 25, 56, ND-25)
Solar Filter (NexStar 114)
Solar Filter (NexStar 4)
Description
General Accessories
RS-232 Cable
Case – Hard (Aluminum)
Case – Tripod, Durable Nylon
Sky Maps
Optical Accessories
Erect Image Diagonal (NexStar 4)
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3
The NexStar 114GT has over twice the light-gathering
power of an 80mm telescope! Compact in design, with
images bright enough to reveal the polar ice caps on Mars
or the cloud belts on Jupiter. View the details of the lunar
surface. The rings of Saturn are clearly visible. With the
extra light gathering capability of the 114GT, a number of
the Messier objects such as the globular cluster in Hercules
(M13), or the Great Nebula in Orion (M42) are available to
you. Begin to explore some of the fainter Messier objects
using the additional light-gathering capabilities of the
114GT’s 4-1/2" primary mirror. Because of the Newtonian
design, the mirror gives fully color-corrected views that
are best suited for astronomical use.
(Shown on optional tripod.)
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with additional eyepieces like the OMNI Plössl eyepieces
or maximize your field of view with the 70° field of view
Add a solar filter to look at sunspots or eyepiece filters
to enhance planetary contrast. Attach a camera to the
NexStar for short exposure astro-photography of the
moon or planets. You might also consider an AC adapter
or car battery adapter to complement the included battery
pack. Don’t forget to protect your investment with a
custom hard shell carrying case.
Item #
94119-10
94119-20
94126-A
94119-A
94134
94129
Item #
93920
302114
302057
93588
93722
94116
93326
94112-A
93320
Description
Photo Accessories
Tripod
Tripod Wedge – NexStar 4
Item #
93625
93497
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NEXSTAR GT
Optical Design
Focal Length
Finderscope
Mount
Eyepiece
Eyepiece
Star Diagonal
Accessory Tray
Tripod
CD ROM
Hand Control
Database
Slew Speeds
31142
NexStar 114GT
11041
NexStar 4GT
700mm f/12
StarPointer
Motorized Altazimuth
1-1/4" – 20mm (35x)
1-1/4" – 10mm, 4mm (70x/175x)
1-1/4"
yes
pre-assembled aluminum
The Sky L1 & NSOL
Fully Computerized
Nine slew speeds: 4º/sec, 2º/sec,
1º/sec, .5 /sec, 32x, 16x, 8x, 4x, 2x
Alt-Az, EQ North & EQ South
Quick-Align
400mm f/5
StarPointer
1-1/4" – 25mm (16x)
1-1/4" – 10mm (40x)
1-1/4"
yes
The Sky L1 & NSOL
Fully Computerized
1º/sec, .5 /sec, 32x, 16x, 8x, 4x, 2x
Quick-Align
1000mm f/9
StarPointer
1-1/4" – 25mm (40x)
1-1/4" – 10mm (100x)
n/a
yes
The Sky L1 & NSOL
Fully Computerized
1º/sec, .5 /sec, 32x, 16x, 8x, 4x, 2x
Quick-Align
102mm (4") Maksutov-Cassegrain
1325mm f/13
StarPointer
1-1/4" – 25mm (53x)
1-1/4" – 10mm (133x)
1.25" w/ flip mirror system
n/a
n/a
The Sky L1 & NSOL
Fully Computerized
1º/sec, .5 /sec, 32x, 16x, 8x, 4x, 2x
Quick-Align
142x
9x
11.4
2.31 arcseconds
1.93 arcseconds
156 lines/mm
73x unaided eye
1.4º
75 ft.
Multi-Coated
n/a
n/a
n/a
28"
9.5 lb.
189x
11x
12
1.73 arcseconds
1.45 arcseconds
364 lines/mm
131x unaided eye
3.25º
171 ft.
Multi-Coated
n/a
n/a
n/a
15.5"
11 lb.
269x
16x
12.8
1.21 arcseconds
1.02 arcseconds
228 lines/mm
265x unaided eye
1.3º
68 ft.
Aluminum
1.6"
13%
36%
19"
15 lb.
240x
15x
12.5
1.36 arcseconds
1.14 arcseconds
140 lines/mm
212x unaided eye
1º
52.5 ft.
Aluminum/Multi-Coated
1.38"
11%
35%
13.5"
11 lb.
3
Dawes Limit
Field of View :standard eyepiece
Optical Coatings
by Area
by Diameter
Optical Tube Length
Telescope Weight
22082
NexStar 80GT
2
Tracking Rates
Tracking Modes
22062
NexStar 60GT
1
SPECIFICATIONS
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NexStar GT – Standard Equipment and Specifications
3
TECHNICAL SPECS
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NEXSTAR 5i
T
he NexStar i Series ushers in a whole new generation of
intelligent telescope design. Simple and friendly to use, the
“i” series is a fully upgradeable system, and can be equipped
with the optional Computerized Hand Control and CN-16 GPS
Accessory for completely automated GoTo function.
Use the Power and
Accuracy of GPS
Satellites to Align
Your Telescope
with the Optional
CN-16 GPS
Accessory (#93963).
Plug this 16-channel
GPS module into your
telescope’s drive
base port to link up
and automatically
download information
from one of many
global positioning
satellites. Controlled
with the NexStar
computerized hand
control, the CN-16
will greatly improve
the accuracy of your
star alignments by
locating north and
leveling the optical
tube with more
precision than can
be done by hand.
Equipped with the standard electronic hand control, you can
manually slew your NexStar across the sky in seconds or track
a star equatorially as the Earth rotates beneath you. The
electronic hand controls allows you to move the telescope at
six different rates and has a “double button” feature that lets
you instantly increase the slew speed without having to change
rates. When used with the optional Computerized Hand Control
these models include all of the same features as our most
advanced GPS and CGE telescope models in an affordable and
expandable system. Most important, these two new NexStars
will fully align themselves when used with the CN-16 GPS
accessory. Put the power of our newest software features and
expanded object database to work for you with Celestron’s
most versatile telescope.
Add the NexStar Hand Control to your NexStar i telescope
and transform it into a completely automated GoTo system.
Just plug it in to access features like automatic star alignment
capability, GoTo slewing to over 40,000 objects and the
expandability to use your NexStar with the external GPS
accessory (CN-16) for a virtually hands-free alignment.
NEXSTAR 8i
Celestron’s optional computerized hand control, with a myriad
of powerful new functions, is the next evolution of the most
user-friendly, intuitive hand control in the industry.
Use Your NexStar i with the Optional Computerized Hand
Control (#93962) to gain these GoTo Features:
Object: Saturn
Instrument: CM1100
Photographer: Damian Peach
• Quick Align – An easy way to get the altazimuth mount
tracking without actually aligning on two stars.
• Hibernate – This power saving device allows you to power
down the telescope without losing your alignment. The
optional CN-16 GPS accessory must be connected. All you
have to do is enter the correct time. Hibernate allows you
to look for planets in the daytime after having used the
telescope the night before or to observe night after night
without having to re-align.
• Database Filter Limits – User-defined so that only objects
visible above the horizon are displayed on the hand control.
• AutoAlign – Automatically aligns the telescope in altazimuth
mode using the optional CN-16 GPS Accessory.
• Wedge Align Algorithm – Automatically aligns the telescope
to the celestial pole. Essential when you are performing a
polar alignment on an equatorial wedge.
• Auto North and Level Compatible – Automatically finds
North and Level with more precision than can be done by
hand, getting you closer to your alignment stars.
• User-Defined Slew Limits – Prevents the telescope from
slewing beyond the user-defined horizon in altazimuth
and equatorial mode.
• Cord Wrap – Prevents the telescope from wrapping its cords
when attaching optional accessories.
• Dozens of Other Powerful Features
• 40,000 Object Database – The expanded, programmable user
database includes the complete Messier, NGC, IC and Caldwell
catalogs. Customized lists of all the best galaxies, nebulae and
other deep-sky objects. Room for hundreds of user defined
objects.
NEXSTAR i
TELESCOPES
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NexStar 5i Schmidt-Cassegrain Telescope
NexStar 8i Schmidt-Cassegrain Telescope
(#11033)
(#11021)
1
Optional
CN-16 GPS Accessory
(#93963)
Optional
(#93962)
With 2.5 times the light gathering of the 5" model, the
NexStar 8i will enable you to see deeper into the
Universe than ever before. The distinctive patented fork
arm with ergonomically designed integrated hand control
cradle gives solid support to Celestron’s classic 8" optics.
The NexStar 8i features Schmidt-Cassegrain 8" aperture
optics with StarBright multi-coating, powerful 2,032mm
focal length and f/10 focal ratio. Ready to take the
optional Computerized Hand Control, the NexStar 8i has
all the same feature as Celestron’s most advanced
computerized GoTo telescopes, including AutoAlign twostar alignment, a sky tour feature, a database of over
40,000 celestial objects and easy to use hand control. Plug
the optional CN-16 GPS Accessory into NexStar’s auxiliary
port and download data from orbiting GPS satellites for
truly hands-free alignments. The universe may be full of
mysteries, but using the NexStar 8i isn’t one of them.
2
A breakthrough in GoTo telescope design, the NexStar
5i features Schmidt-Cassegrain 5" aperture optics with
StarBright multi-coating, powerful 1,250mm focal length
and f/10 focal ratio. Ready to take the optional
Computerized Hand Control, the NexStar 5i expands into
a fully automated GoTo telescope. With features like
AutoAlign two-star alignment, a sky tour feature, a
database of over 40,000 celestial objects and easy to use
hand control, the NexStar 5i is the perfect combination
of power and portability.
SPECIFICATIONS:
8i STANDARD ACCESSORIES INCLUDE:
SPECIFICATIONS:
1-1/4" – 25mm Plössl (50x) Eyepiece
90° 1-1/4" Star Diagonal
1-1/4" Visual Back
Electronic Hand Control
127mm (5") diameter Schmidt-Cassegrain
Focal Length of 1250mm
Focal Ratio of f/10
Six slew speeds: 6º /sec, 2º /sec, 128x, 64x, 16x, 8x
Fully enclosed high speed motors on both axes
Integrated hand controller built into the side of the fork arm
StarBright Multi-Coating
Designated AutoGuider port
Auxiliary Port for optional Accessories, including CN-16 GPS module
Battery Compartment for 8 (user supplied) AA batteries
Weight: 17.6 lb.
1-1/4" – 25mm Plössl (81x) Eyepiece
90° 1-1/4" Star Diagonal
1-1/4" Visual Back
203mm (8") diameter Schmidt-Cassegrain
Focal Length of 2032mm
Focal Ratio of f/10
Six slew speeds: 6º /sec, 2º /sec, 128x, 64x, 16x, 8x
Fully enclosed high speed motors on both axes
Integrated hand controller built into the side of the fork arm
Designated AutoGuider port
Auxiliary Port for optional Accessories, including CN-16 GPS module
Battery Compartment for 8 (user supplied) AA batteries
Weight: 24 lb.
Description
Filters
(12, 25, 56, ND-25)
Solar Filter – NexStar 5
Solar Filter – NexStar 8
General Accessories
CN-16 GPS Accessory
PowerTank 12v Power Supply
Description
AC Adapter
Car Battery Adapter
Case – Hard
Case – Hard, Waterproof
VSP – Vibration Suppression Pad
Sky Maps
Optical Accessories
Barlow Lens, 2X 1-1/4" Ultima
Eyepiece – OMNI Plössl Series 1-1/4" - 15mm
3
5i STANDARD ACCESSORIES INCLUDE:
Item #
94119-10
94119-20
94126-A
94119-A
94139
94162
93962
93963
18774
Item #
18773
18769
302080
302068
93588
93503
93722
93326
93506
94112-A
93320
Description
Eyepiece – OMNI Plössl Series 1-1/4" - 9mm
Eyepiece – Axiom 1-1/4" – 40mm (2")
Eyepiece – Ultima 1-1/4" – 35mm
Photo Accessories
Reducer/Corrector f/6.3
T-Adapter – SCT
Microguide Eyepiece
Tripod
Tripod/Wedge – NexStar 5i
Tripod – NexStar 8i
Item #
93318
93357
93364
93355
93690
4
The Computerized Hand Control is a must to take full
advantage of all the NexStar i features and functions. You
can widen the field of view with 70° Axiom eyepieces. Add
some eyepiece filters like a Light Pollution Reduction (LPR)
filter to minimize the effects of city lights or a moon filter
to reduce the lunar brightness. Add a solar filter to look at
sunspots or the eyepiece filters to enhance planetary
contrast. You might also consider the PowerTank 12v power
supply to power your scope at your favorite dark sky
observing site. Celestron offers a wide array of photographic
accessories compatible with all NexStar i telescopes.
94175
93633-A
94171
93497
93593
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A
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OPTIONAL COMPUTERIZED HAND CONTROL (#93962) SPECS
2
TECHNICAL SPECS
3
SPECIFICATIONS
4
NEXSTAR i
1
D
NexStar i – Standard Equipment and Specifications
1
30
C
B
Optical Design
Focal Length
Finderscope
Mount
Motor Drive
Optical Tube
Eyepiece
Star Diagonal
Slew Speeds
Tracking Modes
Hand Control
Dawes Limit
Field of View: Standard Eyepiece
Optical Coatings
by Area
by Diameter
Optical Tube Length
Power Requirements
Idle Current
Slew One Axis
Slew Both Axes
Telescope Weight
Hand Control
Slew speeds
Software Precision
Ports
Tracking Rates
Tracking Modes
Database
Power Requirements (Telescope
and Computerized Hand Control)
Idle Current
Slew One Axis
Slew Both Axes
Power Requirements of the
Optional CN-16 GPS Accessory
11033
NexStar 5i
11021
NexStar 8i
5" Schmidt-Cassegrain
1250mm f/10
StarPointer
Altazimuth, Fork Arm
Integrated Dual Axis Servo
Aluminum
1-1/4" – 25mm Plössl (50x)
1-1/4"
Six slew speeds: 6º/sec, 2º/sec, 128x, 64x, 16x, 8x
Alt-Az, EQ North, EQ South, Off
2032mm f/10
StarPointer
Altazimuth, Fork Arm
Integrated Dual Axis Servo
Aluminum
1-1/4" – 25mm Plössl (81x)
1-1/4"
Six slew speeds: 6º/sec, 2º/sec, 128x, 64x, 16x, 8x
Alt-Az, EQ North, EQ South, Off
300x
18x
13
1.1 arcseconds
.91 arcseconds
200 lines/mm
329x unaided eye
1º
52.5 ft.
StarBright Coating
1.75"
12%
35%
11"
12VDC 1.5A
115mA
310mA
560mA (with 1A spikes)
17.6 lb.
480x
29x
14
.68 arcseconds
.57 arcseconds
200 lines/mm
843x unaided eye
.63º
33 ft.
StarBright Coating
2.5"
10%
31%
17"
12VDC 1.5A
115mA
310mA
24 lb.
Double line, 16 character Liquid Crystal Display;
19 fiber optic backlit LED buttons
Nine slew speeds: 6º/sec, 3º/sec, 1.5º/sec, 128x, 64x, 16x, 8x, 2x, 1x
24bit, 0.08 arcsec calculations
2-Star Alignment, AutoAlign, EQ North/South and GPS Align
(with optional CN16 GPS Accessory)
40,000+ objects; 400 user defined programmable objects;
enhanced information on over 200 objects
12VDC 1.5A
19 fiber optic backlit LED buttons
Nine slew speeds: 6º/sec, 3º/sec, 1.5º/sec, 128x, 64x, 16x, 8x, 2x, 1x
2-Star Alignment, AutoAlign, EQ North/South and GPS Align
(with optional CN16 GPS Accessory)
40,000+ objects; 400 user defined programmable objects;
enhanced information on over 200 objects
12VDC 1.5A
170mA
360mA
120mA
170mA
360mA
120mA
SPECIFICATIONS:
NEXSTAR 8 GPS
T
DATABASE
Complete
Revised
NGC
Catalog
7,840
Complete
Messier
Catalog
110
Complete IC
Catalog
5,386
Complete
Caldwell
Abell
Galaxies
Solar System
objects
109
2,712
9
Famous
Asterisms
20
Selected CCD
Imaging
Objects
25
Selected SAO
Stars
29,500
Total Object
Database 45,492
he NexStar GPS series is the culmination of years of
engineering research and development delivering the
ultimate instrument in GoTo technology. For the first time in a
commercial telescope, Celestron combines an integrated Global
Positioning System with its legendary Schmidt-Cassegrain
optics to deliver the most advanced telescope on the market
today. The NexStar GPS is so advanced that after you turn it on,
the internal GPS receiver links up and acquires information
from orbiting GPS satellites. With this information the system
automatically downloads the date and time and pinpoints its
exact location on Earth. All the information the NexStar needs
to orient itself with the sky and point to your first alignment
star. No need to enter the date, time, longitude and latitude or
even know the position of north. Once aligned, the NexStar has
a key on the hand control to allow direct access to each of the
catalogs in its user-friendly database. Messier objects, NGC
Galaxies or planets, the NexStar database has over 40,000
celestial objects to choose from. To make navigating through
this expansive database quicker and easier, NexStar has userdefinable database filter limits. With the “filter limits” feature
the NexStar database will display only those objects that are
above the horizon for your exact date, time and location.
On all Fastar compatible NexStar models (8GPS and 11GPS), the
Cassegrain secondary mirror mounted in the middle of the
Schmidt corrector lens is removable. By replacing the secondary
mirror with the optional Fastar Lens Assembly and a CCD
camera, you can transform your NexStar into an ultra fast,
wide-field f/2 imaging system. See Appendix section for more
information on the benefits of the Fastar optical system.
Celestron’s scratch resistant carbon fiber optical tubes provide
excellent thermal expansion properties over aluminum that
help maintain the sharp focus needed for stunning CCD
imagery. Couple these mechanical features with other
performance features like a designated autoguider port,
permanent periodic error correction and equatorial alignments,
and your NexStar GPS would please any serious amateur or
college astronomy program.
NEXSTAR 9 1 / 4 GPS
NEXSTAR 11 GPS
“We ran through the alignment procedure during evening
twilight and observed throughout the entire night without
missing a beat…and every object that we commanded the
scope to point at ended up in the field of a low-power
eyepiece.” Sky & Telescope, February 2002
Celestron knows that the whole is greater than the sum of its
parts. That’s why Celestron designed the NexStar GPS
telescopes from the ground up with features and performance
that add up to a whole lot more telescope than anything else
out there. Celestron is the only manufacturer to offer carbon
fiber optical tubes, meticulously matched and hand-figured
optical systems and high efficiency StarBright coatings.
“The optics in the NexStar loaned to us were some of the finest
I can recall in a Schmidt-Cassegrain, but if anything the optics
in the scope we purchased at random were even better.”
Sky & Telescope, February 2002
NEXSTAR GPS
TELESCOPES
Object: M42
Instrument: NexStar 11 GPS
Photographer: Danyal Medley
31
Other NexStar GPS Capabilities Include:
Mechanical Features:
• Internal Slip Ring – NexStar’s power cables and telescope
accessory cables will not get wrapped around the telescope.
• Integrated Handles – Prevents the power cables from
wrapping inside the base and eliminates the need for
internal hard stops.
• Bearing and Shaft – Stainless steel worm shaft has 0.4375
pitch diameter and is preloaded with two ball bearings.
The worm is made from a single piece of steel (rather than
a two-piece worm-and-shaft assembly) to minimize run-out,
which is a source of periodic error.
• Heavy-Duty Aluminum Spring Loaded Worm Block – On both
axes to minimize backlash.
• Drive Motors – Made in the U.S.A.; Pittman® LO-COG™
brush-commutated DC motors offer smooth, quiet operation
and long life. The motor armatures are skewed to minimize
cogging which is required for low speed tracking. Windings
are resin impregnated for greater reliability in incremental
motion applications.
• Precision Bronze Worm Wheel – 32 pitch, 5.625” pitch
diameter, 180 tooth bronze gear manufactured in the U.S.A.
by W. M. Berg, Inc. Manufactured to AGMA Quality Class 10
standard that minimizes total composite error and backlash.
• Unique Roller Bearing Design – Telescope base rotates around
a wide 9.5” track for maximum stability, especially important
when equatorially mounting for imaging.
• Leveling – Leveling accuracy, which applies to both altazimuth
and equatorial mounts, is accomplished by an internal switch
that levels the base to an accuracy of 1 arcminute.
• Auxiliary Ports – NexStar’s auxiliary ports are located on top
of the base that rotates as the telescope turns, preventing
accessory cables from wrapping around the fork arms.
• Schmidt-Cassegrain mechanism that moves the primary
mirror to adjust focus is supported by two pre-loaded ball
bearings, minimizing the “mirror flop” typical of bushing
focus mechanisms.
• Optical Tube Assembly Outer Rails – An outer rail on each side
of the optical tube provides rigid, flex-free movement. The
mounting tolerance allows the cell to contract and expand.
Electronic and Software Features:
• 16-Channel GPS – The GPS unit pinpoints your exact location
on Earth, while downloading the date and Universal Time
down to the second.
• Hand Control and Software Features – 40,000-object
database. Features include: Compass Calibration, Polar
Alignment routine, Equatorial Auto Align, Database Filter
Limits, Hibernate, Auto North and level, Wedge Align
algorithm, Quick Align, and user-defined slew limits.
• Motor Control Board – Each axis is controlled by an 8- bit
microcontroller. Nine slew speeds: 3º/sec, 2º/sec, .5º/sec, 64x,
16x,8x, 4x, 1x, .5x.
“When it comes to an advanced instrument outfitted with all
of the bells and whistles, the NexStar 8 GPS is a leader in the
field thanks to its easy set-up, ergonomically friendly design,
crisp optics, and intelligent options. Any amateur astronomer
who enjoys an automated tour across the sky, astrophotograpy,
or even a casual star-hop across the universe (and that’s just
about all of us) will find that the high-tech NexStar 8 GPS
provides good old-fashioned fun.” Astronomy, January 2003
A
PAG E NU MBE R
1
C
B
NexStar 8GPS
D
1
The NexStar 8GPS Schmidt-Cassegrain Telescope is
part of Celestron’s “Top-of-the-Line” fork-mounted
astronomical telescopes. This telescope is at home as a
superb visual instrument or, with optional CCD cameras,
as a serious scientific research tool. Besides seeing all of
the Messier Catalog objects, you can also see hundreds
of other, less famous, but equally interesting NGC, IC
and Caldwell objects. Turn this scope to the planets and
see amazing detail on the surface of Jupiter; see Cassini’s
Division in the rings of Saturn, and resolve details on the
surface of Mars. Even the distant Uranus, Neptune and
Pluto are within your reach. Although large in aperture,
with its conveniently located carrying handles and an
instrument weight of only 42lb., this telescope is portable
enough to set up in your backyard or take with you to
your favorite dark sky location.
(#11052)
STANDARD ACCESSORIES INCLUDE:
2
1-1/4" Star Diagonal
1-1/4" Visual Back
AC Adapter (car battery adapter is included with some models)
Heavy Duty Tripod
SPECIFICATIONS:
3
8" (203.2mm) Schmidt-Cassegrain Optical Design
StarBright Multi-Coatings
Dual Fork Arm
Carbon Fiber Optical Tube
Fastar Compatible for f/2 CCD Imaging
19 fiber optic backlit Computer Hand Control
Auxiliary Port and Autoguide Port on Drive Base
16 channel GPS Receiver
Fork Tine and Optical Tube Weight – 42 lb.
about the objects stored in the NexStar hand control
database. A Barlow lens is available to increase the
magnification of your existing eyepieces. Add a focus
motor for hands-off focusing. To attach a camera,
there’s a T-Adapter.
Description
Filters
(12, 25, 56, ND-25)
Solar Filter 8GPS
General Accessories
PowerTank 12v Rechargeable Power Supply
Car Battery Adapter
Lens Shade – Rugged Plastic
Item #
94119-10
94119-20
94126-A
94127-A
94119-A
94162
18774
18769
94019
Description
Lens Shade – Soft
Sky Maps
Optical Accessories
Item #
94012
93588
93722
93326
94112-A
93519
93357
93362
93359
93365
93690
Description
Photo Accessories
Focus Motor
Microguide Eyepiece
Piggyback Adapter
Radial Guider
T-Adapter – SCT
Wedge
Wedge – Heavy Duty
Wedge – Upgrade Kit for 93655
Item #
94142
94171
93598
94176
94175
93633-A
4
with additional eyepieces. You can widen the field of view
with Axiom eyepieces. Add some eyepiece filters like a
Light Pollution Reduction (LPR) filter to minimize the
effects of city lights or a moon filter to reduce the lunar
brightness. Add a solar filter to look at sunspots or eyepiece
filters to enhance planetary contrast. You might also
consider the PowerTank 12v rechargeable power supply or
car battery adapter for using your NexStar in the field.
93655
93662
33
A
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C
NexStar 91/4 GPS
D
The NexStar 91/4 GPS Schmidt-Cassegrain Telescopes
provides 33% more light gathering than the 8" model
and is a favorite among astrophotographer for its razor
sharp views. The NexStar 91/4 GPS optical tube was
specifically optimized for sharp visual and photographic
use. Its longer primary focal length and lower magnification
secondary mirror contributes to a flatter field of view and
helps to further reduce optical aberrations. The optimized
baffling system benefits astrophotography and gives
high contrast views of the planets. The NexStar 91/4
GPS is compatible with the complete line of Celestron
photographic and visual accessories with capabilities
designed to expand as your interest in astronomy grows.
(#11056)
4
1
B
3
1-1/4" – 40mm Eyepiece (59x)
1-1/4" Visual Back
AC Adapter (car battery adapter included in some models)
Heavy Duty Tripod
SPECIFICATIONS:
2
9.25" (235mm) Schmidt-Cassegrain Optical Design
Dual Fork Arm
1
34
You might want to expand your magnification choices with
additional eyepieces. You can widen the field of view with
Celestron offers a whole array of photo accessories, from
piggyback adapters to the Radial Guider off-axis guider.
Improve your field of view and image brightness with the
f/6.3 focal reducer.
Description
Filters
(12, 25, 56, ND-25)
General Accessories
Car Battery Adapter
Sky Maps
Item #
94119-10
94119-20
94126-A
94127-A
18774
18769
93588
93722
Description
Optical Accessories
Diagonal – Mirror 2”
Eyepiece – Axiom 2” – 19mm
Eyepiece – Axiom 2” – 50mm
Item #
93326
94112-A
93519
93357
93362
93359
93365
93690
Description
Photo Accessories
Focus Motor
Microguide Eyepiece
Piggyback Adapter
Radial Guider
T-Adapter – SCT
Wedge
Item #
94142
94171
93598
94176
94175
93633-A
93655
93662
A
PAG E NU MBE R
1
C
B
NexStar 11GPS
D
1
The largest aperture of the GPS line, The NexStar 11GPS
Schmidt-Cassegrain telescope, has the most lightgathering power and has a limiting magnitude of nearly
15. The NexStar 11 GPS takes full advantage of its vast
database of thousands of NGC and Abell galaxies as well
as delivering a new level of detail to all your favorite
deep sky objects. Used in the Fastar configuration for
f/2 CCD imaging, the NexStar 11 can display the faint
detail of a telescope twice its aperture used visually. With
sophisticated software features like Hibernate function,
the NexStar can maintain its star alignment night after
night without needing to be re-aligned, making it an
ideal instrument for a permanent observatory facility.
(#11053)
2
1-1/4" – 40mm Eyepiece (70x)
1-1/4" Visual Back
AC Adapter (car battery adapter included in some models)
Heavy Duty Tripod
SPECIFICATIONS:
3
11" (279mm) Schmidt-Cassegrain Optical Design
Dual Fork Arm
Description
Filters
(12, 25, 56, ND-25)
General Accessories
Car Battery Adapter
Sky Maps
Item #
94119-10
94119-20
94126-A
94127-A
94119-A
18774
18769
93588
93722
Description
Optical Accessories
Item #
93326
94112-A
93519
93357
93362
93359
93365
93690
Description
Photo Accessories
Focus Motor
Microguide Eyepiece
Piggyback Adapter
Radial Guider
T-Adapter – SCT
Wedge
Item #
94142
94171
93598
94176
94175
93633-A
4
with the Axiom 2” 70° eyepieces and the thread-on SCT
mirror diagonal. Add some eyepiece filters like a Light
An equatorial wedge is essential for precise tracking for
Fastar CCD or traditional photographic use. Include a focus
motor for easy hands-free focusing.
93655
93662
35
A
PAG E NU MBE R
SPECIFICATIONS
4
NEXSTAR GPS
Optical Design
Focal Length
Finderscope
Mount
Optical Tube
Fastar Compatible
Eyepiece
Star Diagonal
Tripod
AC Adapter
Computer Hand Control
Hand Control Ports
Motor Ports
Database
GPS
3
Motor: Type
Resolution
Slew Speeds
Software Precision
Tracking Rates
Tracking Modes
Dawes Limit
Field of View :standard eyepiece
Optical Coatings
by Area
by Diameter
Optical Tube Length
Telescope Weight
Tripod/Mount Weight
11052
NexStar 8 GPS
11056
NexStar 91/4 GPS
11053
NexStar 11 GPS
2032mm f/10
9x50
Dual Fork Arm
Carbon Fiber
Yes
1-1/4" – 40mm Plössl (51x)
1-1/4"
Heavy Duty Adjustable
Included
Double line, 16 character Liquid
Crystal Display; 19 fiber optic
backlit LED buttons
RS-232 communication port
on hand control
16 channel
9.25" Schmidt-Cassegrain
2350mm f/10
9x50
Dual Fork Arm
Carbon Fiber
No
1-1/4" – 40mm Plössl (59x)
1-1/4"
Included
backlit LED buttons
on hand control
16 channel
2800mm f/10
9x50
Dual Fork Arm
Carbon Fiber
Yes
1-1/4" – 40mm Plössl (70x)
1-1/4"
Included
backlit LED buttons
on hand control
16 channel
DC Servo motors with encoders,
both axes
.1125 arcsecond
.5º/sec, 64x, 16x, 8x, 4x, 1x, .5x
Altazimuth, EQ North & EQ South
Quick Align
480x
29x
14
.68 arcseconds
.57 arcseconds
200 lines/mm
843x unaided eye
1º
52.5 ft.
StarBright Coating
2.7"
11%
34%
17"
42 lb.
19 lb.
both axes
.1125 arcsecond
.5º/sec, 64x, 16x, 8x, 4x, 1x, .5x
Quick Align
555x
34x
14.4
.59 arcseconds
.49 arcseconds
200 lines/mm
1127x unaided eye
.88º
46 ft.
StarBright Coating
3.35"
13%
36%
22"
58 lb.
19 lb.
both axes
.1125 arcsecond
.5º/sec, 64x, 16x, 8x, 4x, 1x, .5x
Quick Align
660x
40x
14.7
.50 arcseconds
.42 arcseconds
200 lines/mm
1593x unaided eye
.46º
24 ft.
StarBright Coating
3.75"
12%
34%
23"
65 lb.
19 lb.
SPECIFICATIONS:
1
TECHNICAL SPECS
D
NexStar GPS – Standard Equipment and Specifications
1
2
C
B
36
CGE 800
T
DATABASE
Complete
Revised NGC
Catalog
7,840
Complete
Messier
Catalog
110
Complete IC
Catalog
5,386
Complete
Caldwell
109
Abell
Galaxies
2,712
Solar System
Objects
9
Famous
Asterisms
20
Selected CCD
Imaging
Objects
25
Selected
SAO Stars
29,500
Total Object
Database 45,492
he CGE computerized series is Celestron’s newest line of
observatory class Schmidt-Cassegrain telescopes. Offered
in 8", 91/4", 11" and 14" apertures, they all come mounted on
the state of the art CGE GoTo German Equatorial mount. The
German Equatorial mount has long been the favored choice of
astronomy buffs and astrophotographers because of its stability
and portability. More stable because the center of gravity is
directly over the center of its base, more portable because it
can be broken down into smaller component parts for easy
storage and transportation. For astrophotography, the German
Equatorial mount offers easier balancing, unlimited space at
the rear of the telescope tube to mount a camera, and whole
sky access. Now you can enjoy all of the NexStar software and
database features with the extra stability and portability of a
German equatorial Mount.
The Celestron CGE telescopes use the same optical tube assembly
(OTA) as the 8GPS, C91/4-S and 11GPS telescopes while the CGE
1400 uses the classic C14" optical tube assembly. All include high
efficiency StarBright coatings. The 8", 11" and 14" all have
Fastar compatible optics for wide field f/2 CCD imaging.
In addition to being fully computerized with a database of over
40,000 celestial objects, the CGE German Equatorial Mount
offers numerous design advantages:
Portability – Set up and transportation of the CGE telescopes
is made easy by separating the CGE instruments into smaller,
easy-to-carry components. Unlike fork arm mounted telescopes,
the CGE’s optical tubes can be quickly removed from their
mounts making even the CGE 1400 easily assembled by only
one person.
Stability – Recognized for superior stability, German Equatorial
Mounts place the center of gravity directly over the tripod legs
and can be easily polar aligned without the use of an optional
equatorial wedge. This proven design reduces the “tuning fork”
vibration that can be associated with undersized fork mounts.
Object: M33
Instrument: CGE 1400
Photographer: Richard Hedrick
The CGE mount is supported by an improved Super HD Tripod.
This fully extendable tripod is made from the finest cold rolled
carbon steel and can be raised to a height of 50". The tripod
uses a dual leg support for maximum rigidity with an upper leg
brace to provide an outward preload and a lower leg brace
providing inward tension.
Balance – CGE equatorials mounts can easily be balanced in
both axes. Balancing the weight of camera equipment and
other visual accessories is accomplished by simply sliding the
counterweight for Right Ascension and moving the optical tube
along its dovetail mounting for Declination. This means that no
additional weight needs to be added to balance the telescope
when additional accessories are added.
Clearance – CGE mounts support their tubes at a single contact
point allowing the tube to move freely around its polar axis
without making contact with the telescope’s mount. This is
particularly useful when adding photographic and CCD
instruments that extend from the rear of the telescopes.
CGE 925
CGE 1100
CGE 1400
All CGE mounted telescopes are compatible with Celestron’s
CN-16 GPS accessory. Combine the GPS and built-in Hibernate
mode and these telescopes will keep track and remember their
exact location and time without having to enter the
information into the hand control.
CGE
TELESCOPES
37
Other CGE Capabilities Include:
RA and Dec Axis
Mechanical Features
• 1" solid ground stainless steel shaft.
• Two preloaded 0.9835" I.D. x 2.047" O.D. tapered roller bearings.
• One 3.543" I.D. x 4.724" O.D. thrust bearing (RA Axis).
• 180 tooth, 5.625 pitch diameter enveloping bronze gear
preloaded to maintain gear mesh when clutch tension varies,
manufactured to AGMA 10 quality by W.M. Berg.
• 0.4375" diameter precision 303 stainless steel worm
manufactured to AGMA 10 quality.
• Four point RA clutch system pre-loading a 4.65" stainless
steel disk for no-slip drive and pointing precision.
• One 2.500" I.D. x 3.250" O.D. thrust bearing (Dec Axis).
• Carbon Fiber Tube – Strong and lightweight with 1/4 the
thermal expansion of an aluminum tube on the 8" and 11"
models. Scratch and dent resistant.
• CNC machined aluminum and stainless steel components
• Autoguide port, PC port and auxiliary ports located on
the electronic pier.
• Strain relief power cord cable protection
• Backlit power switch
• Drive Motors – Made in the U.S.A., Pittman® LO-COG™
brush-commutated DC motors offer smooth, quiet operation
and long life. The motor armatures are skewed to minimize
cogging which is required for low speed tracking. Windings
are resin impregnated for greater reliability in incremental
motion applications.
• Precision Bronze Worm Gear – 32 pitch, 5.625" pitch
diameter, 180 tooth bronze gear manufactured in the U.S.A.
by W. M. Berg, Inc. Manufactured to AGMA Quality Class 10
standard, which minimizes total composite error and backlash.
• Bearing and Shaft – Stainless steel worm shaft has 0.4375
pitch diameter and is preloaded with two ball bearings.
The worm is made from a single piece of steel (rather than
a two-piece worm-and-shaft assembly) to minimize run-out,
which is a source of periodic error.
• 4 point RA clutch system for no-slip pointing precision
• Schmidt-Cassegrain mechanism that moves the primary
mirror to adjust focus is supported by two pre-loaded ball
bearings, minimizing the “mirror flop” typical of bushing
focus mechanisms.
• Latitude range: 10º to 60º northern or southern hemisphere
• Maximum payload: 65 lb.
Object: Horsehead Nebula
Instrument: CGE 1400
Tripod
• Adjustable height: 36" to 50".
• Leg material: cold rolled carbon steel.
• Upper leg diameter: 2.75"; lower leg diameter: 2.375".
Electronic and Software Features
• GoTo system is precision accurate to 1.5 arcminutes.
• 40,000-object database with 400 user-defined objects.
Features include: Compass Calibration, Polar Alignment
routine, Database Filter Limits, Hibernate, Auto North and
Level, Quick Align, and user-defined slew limits.
• Hibernate – maintains alignment even while powered down.
• Polar alignment routines for Northern and Southern
hemispheres.
• Filter limits – displays only objects above the horizon.
• Permanent programmable periodic error correction
(PEC) – corrects for periodic tracking errors inherent
to all worm drives.
• Smooth ramping of slew motors to reduce wear on the
drive train.
• Home sensors on R.A. and Dec axes.
• Fail-safe slew limit switches in R.A.
• Real-time clock – maintains time even when powered down.
• 12VDC Servo Motors with integrated optical encoders with
0.11 arcsecond resolution.
A
PAG E NU MBE R
1
C
B
CGE 800 Schmidt-Cassegrain on a Computerized German Equatorial Mount
D
(#11058)
1
The CGE 800 Schmidt-Cassegrain Telescope is part of
Celestron’s “Top-of-the-Line” German Equatorial mounted
astronomical telescopes. The CGE 800 is the most portable
of the four models. This telescope is especially at home
as a solid platform for long exposure photography with
optional CCD cameras or photographic equipment. Using
an f/6.3 Focal Reducer or Fastar accessory makes it usable
with a wide variety of CCD cameras. German Equatorial
mounts are recognized as being the superior choice
for astrophotography because of their rock solid stability,
simple balancing and easy accessibility for attaching
equipment. This, coupled with the CGE line’s GoTo capability,
makes it an unbeatable instrument for its size.
As a visual instrument you can search for all of the
Messier Catalog objects, and you can see hundreds of
other, less famous, but equally interesting NGC, IC and
Caldwell objects. Turn this scope to the planets and see
amazing detail on the surface of Jupiter; see Cassini’s
Pluto are within your reach.
2
1-1/4" Visual Back
Car Battery Adapter
SPECIFICATIONS:
3
8" (203.2mm) Schmidt-Cassegrain Optical Design
Computerized Equatorial Mount
Super HD Tripod
19 fiber optic backlit Computerized Hand Control
Optical Tube Weight – 12.5 lb.
Tripod/Mount Weight – 100 lb.
about the objects stored in the computerized hand
control database. A Barlow lens is available to increase
the magnification of your existing eyepieces. Add a
focus motor for hands-off focusing. To attach a camera,
there’s a T-Adapter.
Description
Filters
(12, 25, 56, ND-25)
LPR Filter for 1-1/4" Eyepiece
Solar Filter 8GPS
General Accessories
CN-16 GPS Accessory
Lens Shade – Rugged Plastic
Item #
94119-10
94119-20
94126-A
94127-A
94119-A
94162
93963
18774
94019
Description
Lens Shade – Soft
Sky Maps
Optical Accessories
Barlow Lens, 2X 1 1/4" OMNI
Eyepiece – Axiom 1 1/4" – 15mm
Item #
94012
93588
93722
93326
94112-A
93519
93690
93357
93362
93359
93365
Description
Photo Accessories
Focus Motor
Microguide Eyepiece
Piggyback Adapter
Radial Guider
T-Adapter – SCT
Fastar Lens Assembly
Item #
94142
94171
93598
94176
94175
93633-A
94180
4
brightness. Add a solar filter to look at sunspots or eyepiece
filters to enhance planetary contrast. You might also
consider the PowerTank 12v rechargeable power supply
or car battery adapter for using your CGE in the field.
39
A
PAG E NU MBE R
C
D
(#11059)
4
1
B
astronomical telescopes. The larger CGE 925 is still portable
enough to take with you, yet it offers a 33% increase
in light gathering power over 8" telescopes. This telescope
is especially at home as a solid platform for long exposure
photography with optional CCD cameras or photographic
equipment. Using an f/6.3 Focal Reducer makes it usable
with a wide variety of CCD cameras. German Equatorial
mounts are recognized as being the superior choice
for astrophotography because of their rock solid stability,
simple balancing and easy accessibility for attaching
equipment. This, coupled with the CGE line’s GoTo capability,
makes it unbeatable.
3
As a visual instrument you can search for all of the
Messier Catalog objects, and you can see hundreds of
other, less famous, but equally interesting NGC, IC and
Caldwell objects. Turn this scope to the planets and see
amazing detail on the surface of Jupiter; see Cassini’s
Pluto are within your reach.
1-1/4" – 25mm Plössl Eyepiece (94x)
1-1/4" Visual Back
Car Battery Adapter
SPECIFICATIONS:
2
9.25" (235mm) Schmidt-Cassegrain Optical Design
Super HD Tripod
Optical Tube Weight – 20 lb.
1
40
brightness. Celestron offers a whole array of photo
accessories, from piggyback adapters to the Radial Guider
off-axis guider. Improve your field of view and image
brightness 63% with the f/6.3 focal reducer.
Description
Filters
(12, 25, 56, ND-25)
General Accessories
CN-16 GPS Accessory
Car Battery Adapter
Item #
94119-10
94119-20
94126-A
94127-A
93963
18774
18769
Description
Sky Maps
Optical Accessories
Item #
93588
93722
93326
94112-A
93519
93357
93362
93359
93365
93690
Description
Photo Accessories
Focus Motor
Microguide Eyepiece
Piggyback Adapter
Radial Guider
T-Adapter – SCT
Item #
94142
94171
93598
94176
94175
93633-A
A
PAG E NU MBE R
1
B
C
D
(#11061)
2
As a visual instrument you can search for all of the Messier
Catalog, NGC, IC and Caldwell objects. Turn this scope
to the planets and see amazing detail on the surface of
Jupiter; see Cassini’s Division in the rings of Saturn, and
resolve details on the surface of Mars. Even the distant
Uranus, Neptune and Pluto are within your reach.
1
The CGE 1100 Schmidt-Cassegrain Telescope is part
of Celestron’s “Top-of-the-Line” German Equatorial
mounted astronomical telescopes. With the optical tube
assembly of the CGE 1100 weighing only 27.5 lb., this
telescope is still portable enough to be taken to dark
skies, and it has 89% more light gathering power than
an 8” telescope. This telescope is especially at home as
a solid platform for long exposure photography with
optional CCD cameras or photographic equipment; it
is a serious scientific research tool. Using an f/6.3 Focal
Reducer or Fastar accessory makes it usable with a wide
variety of CCD cameras. German Equatorial mounts
are recognized as being the superior choice for astrophotography because of their rock solid stability, simple
balancing and easy accessibility for attaching equipment.
Couple these mechanical features with other performance
features like a designated autoguider port, permanent
periodic error correction and equatorial alignments,
and the CGE 1100 would please any serious amateur
or college astronomy program.
1-1/4" – 40mm Plössl Eyepiece (70x)
1-1/4" Visual Back
Car Battery Adapter
SPECIFICATIONS:
3
Super HD Tripod
Double line, 16 character Liquid Crystal Display
Optical Tube Weight – 27.5 lb.
Description
Filters
(12, 25, 56, ND-25)
Item #
94119-10
94119-20
94126-A
94127-A
94119-A
Description
General Accessories
CN-16 GPS Accessory
Car Battery Adapter
Sky Maps
Optical Accessories
Item #
93963
18774
18769
93588
93722
93326
94112-A
93519
93690
93357
Description
Photo Accessories
Focus Motor
Microguide Eyepiece
Piggyback Adapter
Radial Guider
T-Adapter – SCT
Item #
93362
93359
93365
94142
94171
93598
94176
94175
93633-A
94179
4
with the Axiom 2" 70° eyepieces and the thread-on 2" SCT
mirror diagonal. Add some eyepiece filters like a Light
Include a focus motor for easy hands-free focusing.
41
A
PAG E NU MBE R
C
D
(#11063)
4
1
B
astronomical telescopes. With over three times the light
gathering power of an 8” telescope, this observatory-class
instrument is Celestron’s largest optical system in its class.
This telescope is especially at home as a solid platform for
long exposure photography with optional CCD cameras or
photographic equipment; it is a serious scientific research
tool. German Equatorial mounts are recognized as being
the superior choice for astrophotography because of their
rock solid stability, simple balancing and easy accessibility
for attaching equipment. Used in the Fastar configuration
for f/2 CCD imaging, the CGE 1400 can display the faint
detail of a telescope twice its aperture used visually. With
sophisticated software features like Hibernate function,
the CGE can maintain its star alignment night after night
without needing to be re-aligned, making it an ideal
instrument for a permanent observatory facility.
3
The CGE 1400 takes full advantage of its vast database of
thousands of NGC and Abell galaxies as well as delivering
a new level of detail to all your favorite deep sky objects.
Turn this scope to the planets and see amazing detail on
the surface of Jupiter; see Cassini’s Division in the rings of
Saturn, and resolve details on the surface of Mars. Even the
distant Uranus, Neptune and Pluto are within your reach.
2" – 40mm Eyepiece (98x)
2" Diagonal with 1.25" Adapter
Car Battery Adapter
SPECIFICATIONS:
2
Super HD Tripod
Optical Tube Weight – 45 lb.
1
42
There are a wide variety of accessories available for the
CGE Series of telescopes. Additional eyepieces are the first
accessories most people want for their telescopes. You can
widen the field of view with the Axiom 2" 70° eyepieces.
Eyepiece filters alter the color of light that reaches your
eye. Colored filters improve contrast, improving your ability
to see planetary details. Add a neutral density filter to
reduce the amount of light (very useful when observing
the moon). A Light Pollution Reduction (LPR) filter reduces
the effect of city lights. Several different kinds of nebulae
filters are available to enhance the detail and contrast
when viewing nebulae.
All CGE models are GPS compatible with the use of the
CN-16 GPS accessory.
The f/6.3 Reducer Corrector changes the effective focal
length of the telescope by 63%, lowering photographic
magnification and enlarging the field of view. The f/6.3
Reducer Corrector also reduces the exposure times when
photographing.
Description
Filters
Eyepiece Filter Set – 1-1/4" (12, 25, 56, ND-25)
Item #
94119-10
94119-20
Description
Filters (cont.)
General Accessories
CN-16 GPS Accessory
Car Battery Adapter
Sky Maps
Optical Accessories
Item #
94126-A
94127-A
94119-A
93963
18774
18769
93588
93722
93326
94112-A
Description
Photo Accessories
Microguide Eyepiece
Piggyback Adapter
Radial Guider
T-Adapter – SCT
Item #
93690
93357
93362
93359
93365
94171
93598
94176
94175
93633-A
94181
A
B
PAG E NU MBE R
CGE
Optical Design
Focal Length
Finderscope
Fastar Compatible
Mount
Optical Tube
Eyepiece
Star Diagonal
Tripod
Car Battery Adapter
11061
CGE 1100
11063
CGE 1400
2032mm f/10
6x30
Yes
Carbon Fiber
1-1/4"– 25mm Plössl (81x)
1-1/4"
Adjustable, Carbon Steel
Included
9.25" Schmidt-Cassegrain
2350mm f/10
6x30
No
Aluminum
1-1/4"– 25mm Plössl (94x)
1-1/4"
Included
2800mm f/10
9x50
Yes
Carbon Fiber
1-1/4" – 40mm Plössl (70x)
1-1/4"
Included
3910mm f/11
9x50
Yes
Aluminum
2" – 40mm (98x)
2" with 1-1/4" adapter
Included
SPECIFICATIONS:
480x
29x
14
.68 arcseconds
.57 arcseconds
200 lines/mm
843x unaided eye
.62º
32 ft.
StarBright Coating
2.7"
11%
34%
17"
12.5 lb.
41.5 lb.
42 lb.
5 lb.
1 X 11 lb.
555x
34x
14.4
.59 arcseconds
.49 arcseconds
200 lines/mm
1127x unaided eye
.53º
28 ft.
StarBright Coating
3.35"
13%
36%
22"
20 lb.
41.5 lb.
42 lb.
5 lb.
1 X 25 lb.
660x
40x
14.7
.50 arcseconds
.42 arcseconds
200 lines/mm
1593x unaided eye
.71º
38 ft.
StarBright Coating
3.75"
12%
34%
24"
27.5 lb.
41.5 lb
42 lb.
5 lb.
1 X 25 lb.
840x
51x
15.3
.39 arcseconds
.33 arcseconds
165 lines/mm
2581x unaided eye
.51º
27 ft.
StarBright Coating
4.5"
10%
32%
31"
45 lb.
41.5 lb.
42 lb.
5 lb.
2 X 25 lb.
both axes
backlit LED buttons
.5º/sec, 64x, 16x, 8x, 4x, 1x, .5x
EQ North & EQ South
AutoAlign, 2-Star Align, Quick Align,
1-Star Align, Recall Last Alignment
24bit, 0.08 arcsec calculation
40,000+ objects; 400 user defined
programmable objects; enhanced
information on over 200 objects
12 VDC 1.5A
215mA
600mA
Yes
CN-16 GPS Accessory
both axes
backlit LED buttons
.5º/sec, 64x, 16x, 8x, 4x, 1x, .5x
EQ North & EQ South
40,000+ objects; 400 user defined
12 VDC 1.5A
215mA
600mA
Yes
CN-16 GPS Accessory
both axes
backlit LED buttons
.5º/sec, 64x, 16x, 8x, 4x, 1x, .5x
EQ North & EQ South
40,000+ objects, 400 user defined
12 VDC 1.5A
215mA
600mA
Yes
CN-16 GPS Accessory
both axes
backlit LED buttons
.5º/sec, 64x, 16x, 8x, 4x, 1x, .5x
EQ North & EQ South
40,000+ objects, 400 user defined
12 VDC 1.5A
215mA
600mA
Yes
CN-16 GPS Accessory
3
11059
CGE 925
2
Dawes Limit
Optical Coatings
by Area
by Diameter
Optical Tube Length
Optical Tube Weight
Tripod and Pier Weight
EQ Mount Weight
Counter Weight Bar
Counter Weight
11058
CGE 800
1
SPECIFICATIONS
D
CGE – Standard Equipment and Specifications
1
TECHNICAL SPECS
C
Motor Drive
Slew Speeds
Tracking Rates
Tracking Modes
Software Precision
Database
Power Requirements
Idle Current
Slew One Axis
Slew Both Axes
Internal Clock
GPS Compatible
4
CGE MOUNT SPECIFICATIONS
Computer Hand Control
43
A
C
B
PAG E NU MBE R
D
Optical Tube Assemblies
4
1
C
3
B
A: 9-1/4" Optical Tube Assembly
B: 11" Optical Tube Assembly
C: 14" Optical Tube Assembly
D: 8" Optical Tube Assembly
A
2
Celestron Schmidt-Cassegrain Optical Tube Assemblies
(OTA) are available individually to be used with your
favorite mount. Each OTA is made to the same exacting
standards as those used on all our high quality telescopes.
All optical surfaces are coated with Celestron’s high
efficiency StarBright multi-layered coating group. These
tube assemblies are equipped with the same dove-tail
mounting bar as used on the CGE series for easy
attachment to a variety of popular mounts. Every tube
assembly is made, assembled and quality control tested
at our facility in Torrance, California.
1
SPECIFICATIONS
44
D
Part Number
Focal Length
Eyepiece
Star Diagonal
Finderscope
Optical Tube
Fastar Compatible
Optical Coatings
Secondary Mirror
Obstruction
Optical Tube Length
Optical Tube Weight
8" OTA
91024
2032mm f/10
1-1/4"– 25mm Plössl (81x)
90° – 1-1/4"
6x30
Aluminum
No
2.5" (31% by diameter,
10% by area)
17"
12.5 lb.
8" OTA-CF
91023
2032mm f/10
1-1/4"– 25mm Plössl (81x)
90° – 1-1/4"
6x30
Carbon Fiber
Yes
11% by area)
17"
12.5 lb.
9-1/4" OTA
91027
2350mm f/10
1-1/4" – 25mm Plössl (94x)
90° – 1-1/4"
6x30
Aluminum
No
13% by area)
22"
20 lb.
9-1/4" OTA-CF
91026
2350mm f/10
1-1/4" – 25mm Plössl (94x)
90° – 1-1/4"
6x30
Carbon Fiber
No
13% by area)
22"
20 lb.
11" OTA
91036
2800mm f/10
1-1/4" – 40mm Plössl (70x)
90° – 1-1/4"
9x50
Aluminum
No
12% by area)
24"
27.5 lb.
11" OTA-CF
91035
2800mm f/10
1-1/4" – 40mm Plössl (70x)
90° – 1-1/4"
9x50
Carbon Fiber
Yes
12% by area)
24"
27.5 lb.
14" OTA
91037
3910mm f/11
2" – 40mm Plössl (98x)
90° – 2"
9x50
Aluminum
Yes
10% by area)
31"
45 lb.
ULTIMA 10X50
C
elestron offers binoculars suited for a wide variety of
uses – from astronomy to all sorts of sporting and
recreational uses. Due to their large aperture and quality optics,
certain Celestron binoculars, though appropriate for almost
any use, are designed specifically for astronomy. Binoculars
offer a superb complement to a telescope because they give
exceptionally wide fields of view and lower power that is
difficult to achieve with a telescope. Binoculars can be used
to view the larger and brighter deep space objects such as
the Andromeda Galaxy. They are also a great way to view
wide expanses of the Milky Way or to “star hop” when
searching for some elusive object with your telescope.
Which binocular model fits your needs best?
The brilliance and sharpness of the image you see through a
particular binocular is determined by a number of different
factors. Magnification, optical coatings and lens diameter are
just a few of the factors influencing how a binocular performs.
The single most important criteria, however, in performance will
always be the quality of the optics. Celestron delivers optical
excellence through careful consideration of quality in the glass
and lens coatings used, precision manufacturing processes, and
uncompromising quality control.
Factors to consider when selecting binoculars:
Magnification (Power) — Magnification is the degree to which
the object being viewed is enlarged. For example, with a 7x42
binocular, the number 7 represents the magnification. A power
of 7 magnifies an image to seven times the size it would be
when viewed by the unaided eye. The level of power affects the
brightness of an image, so the lower the power of a binocular,
the brighter the image will be. In general, increasing power will
reduce both the field of view and eye relief.
Diameter (Aperture) — The front lenses of binoculars are the
objective lenses. The diameter of one of these lenses, given in
millimeters, will be the second number describing a particular
binocular. A 7x42 binocular has an objective lens that is 42mm
Object: Hale-Bopp Comet
Photographer: Dean Koenig
in diameter. The diameter of the objective lens determines the
light gathering ability of the instrument, with the greater light
gathering ability of the larger lens translating into greater
detail and image clarity. This is especially useful in low light
conditions and at night.
Exit Pupil — The diameter, in millimeters, of the beam of light
that leaves the eyepiece of a pair of binoculars is the “exit
pupil.” The larger the exit pupil, the brighter the image will
appear. Having a large exit pupil is advantageous under low
light conditions and at night. For astronomical applications,
the exit pupil of the binocular should correspond with the
size of one’s dark adapted pupil. This number will be between
5mm and 9mm.
Field of View — The size of the area that can be seen while
looking through a pair of binoculars is referred to as the field
of view. The angular field of view is indicated on the outside
of Celestron binoculars, in degrees. The linear field of view,
important in land-based viewing, refers to the area that can
be observed at 1,000 yards and is expressed in feet. You can
calculate the linear field by multiplying the angular field by
52.5. For example, if the angular field of a particular binocular
is 8º, then the linear field of view will be 420 feet (8 times 52.5).
Eye Relief — This refers to the distance, in millimeters, that a
binocular can be held from the eye with the full field of view
still comfortably observed. Eyeglass wearers in particular benefit
from longer eye relief.
ULTIMA 8X56
ULTIMA 9X63
SkyMaster 15X70
SkyMaster 20X80
SkyMaster 25X100
ASTRO
BINOCULARS
45
A
C
B
D
PAG E NU MBE R
1
Ultima Series
4
SkyMaster Series
A
A
B
3
B
C
C
2
The Ultima and SkyMaster series feature BAK-4 Porro
Prisms for the brightest possible images. Both models of
binoculars are layered with high transmission multicoatings and have long eye relief for comfortable viewing.
The SkyMaster series offers extra large aperture and higher
magnification and consequently requires a tripod for jitterfree use. Although fully at home when looking at the stars,
they are also superb instruments for terrestrial viewing,
especially when viewing under low light conditions or at
extreme distances.
A: Ultima 8X56 (#71126)
B: Ultima 10X50 (#71127)
C: Ultima 9X63 (#71128)
1
SPECIFICATIONS
46
Type
Size
Prism
Coating
Weatherproof
Angular FOV°
Linear FOV (ft.@1,000 yd.)
Exit Pupil (mm)
Eye Relief (mm)
Near Focus (ft.)
Weight (oz.)
ULTIMA 10X50 (#71127)
ULTIMA 8X56 (#71126)
ULTIMA 9X63 (#71128)
Porro
10X50
BAK4
Fully Multi-Coated
Water Resistant
5
263
5
21
29
27
Porro
8x56
BAK4
Fully Multi-Coated
Water Resistant
6.1
320
7
21
30
31
Porro
9x63
BAK4
Fully Multi-Coated
Water Resistant
5.4
283
7
21
30
35
SPECIFICATIONS
Type
Size
Prism
Coating
Weatherproof
Angular FOV°
Linear FOV (ft.@1,000 yd.)
Exit Pupil (mm)
Eye Relief (mm)
Near Focus (ft.)
Weight (oz.)
A: SkyMaster 15X70 (#71009)
B: Sky Master 25X100 (#71017)
C: Sky Master 20X80 (#71016)
SkyMaster 15X70 (#71009)
Porro
15x70
BAK4
Multi-Coated
Water Resistant
4.4
230
4.7
18
43
48
Porro
20x80
BAK4
Multi-Coated
Waterproof
3.3
173
4
15
51
82
Porro
25x100
BAK4
Multi-Coated
Waterproof
3
157
4
15
80
157
A
C
B
PAG E NU MBE R
D
Appendix
1
Although there are many amateurs who still use film, by far the most prevalent movement is towards CCD
(Charged-Coupled Device) imaging. CCD cameras are available to fit most budgets and have light sensitive detectors
capable of producing images far beyond the capabilities of film. One of the main limitations of CCD imaging is
the small size of the CCD chips and the narrow field of views they produce. This of course can be overcome by
using CCD cameras with large and very expensive imaging chips. Alternatively, a standard size CCD camera can be
effectively used if coupled with a telescope of sufficient light gathering power and a short focal length.
In keeping with its tradition of innovation, Celestron is the first manufacturer to equip select Schmidt-Cassegrain
optical tubes with a removable secondary mirror allowing you to place a lens assembly and CCD camera at the
prime focus of the primary mirror. This unique optical configuration, called Fastar, not only allows you to use your
Schmidt-Cassegrain Telescope at many different photographic focal lengths, but also gives the ability to take
wide-field images at an amazing f/2 imaging speed.
Wider Field
The photographic field of view of a telescope is determined by the telescope’s focal length and the size of the
CCD chip. CCD’s are made up of many individual cells called pixels arranged in rows and columns. The size and
number of pixels along with the focal length of the telescope determine the field of view and resolution. Pixel
size in commercially available CCD cameras for astro-imaging ranges from about 7 microns (.007mm) to about 25
microns (.025mm). The formula for photographic field of view is:
Photographic Field of View (in degrees) = ((CCD Dimensions in mm) (Telescope Focal Length in mm)) x 57.3
Let’s compare the field of view of a standard size CCD chip when used on a Fastar compatible NexStar 8GPS at
both f/10 and f/2:
Assuming the CCD chip is 4.7mm on it longest axis and knowing the telescope focal length is 2000mm:
Photographic Field of View = (4.7 / 2000) x 57.3 = .135 degrees (8.1 arcminutes)
Using the same CCD chip in the Fastar configuration at f/2 (400mm), the field of view would be:
2
Photographic Field of View = (4.7 / 400) x 57.3 = .67 degrees (40 arcminutes).
1. Visual - Optical tube shown in the traditional
configuration for visual use, with the secondary
mirror installed and the Star Diagonal and Eyepiece
at the rear of the tube.
1
Astrophotography – CCD Imaging and Fastar
Astrophotography has been a standard part of amateur astronomy since its earliest days. Using film, it has been
possible to capture details of many of the hard-to-see deep space objects. Specialized films and processing
procedures are required to counteract the problems caused by long exposure to low levels of light.
The same CCD camera in the Fastar configuration yields a field of view 5 times greater than at the traditional
f/10 position!
Image Scale
Another advantage of having a telescope that can be used in variety of focal lengths is the ability to change the
image scale of the system to suit the type of object being imaged. Each pixel of a CCD chip covers a certain
number of arcseconds of sky; this is called image scale. A typical night’s seeing conditions is usually about 2 - 5
arcseconds. Having an image scale that falls within this range is suitable for most deep sky imaging, however, for
higher resolution planetary and lunar imaging an image scale of less than one arcsecond is desirable.
2. Fastar - f/2 configuration with Fastar Lens
Assembly and optional CCD camera in the place
of the secondary mirror. This arrangement allows
deep-sky CCD imaging at the prime focus of the f/2
primary mirror greatly expanding the field of view
from that of ordinary Cassegrain telescopes.
3. Photography - Shown using Celestron’s many
photographic accessories including the Reducer/
Corrector, Radial Guider, MicroGuide Reticle Eyepiece
and Illuminator for long exposure guided film
photography at f/10 or f/6.3.
Image scale is calculated by the formula:
(205 x Pixel Size in Microns)
3
Image Scale (in arcseconds) =
(Telescope Focal Length in mm)
4. CCD Imaging - Shown with the CCD camera
attached to the rear of the telescope tube, this
configuration gibes you higher magnification
CCD images at f/10 or f/6.3 (with Reducer/
Corrector accessory).
5. Using a CCD camera with a Barlow Lens, you
can take high magnification f/20 planetary and
lunar images.
Image Scale (in arcseconds) = (205 x 7.4) / 2000 = 0.758 arcseconds per pixel
This CCD chip and telescope combination not only gives you high magnification capable of filling the CCD chip
with smaller planetary and lunar objects, but also yields the high resolution needed to reveal fine planetary detail
and structure.
This same camera / telescope combination, this time used in the f/2 Fastar position (400mm focal length at f/2),
gives the following:
Image Scale = (205 x 7.4) / 400 = 3.8 arcseconds per pixel
4
Faster Exposure Time
Just like with traditional film photography, fast f-numbers translate into shorter exposure times. Nowhere else is this
more important that when accurately tracking the sky while imaging deep-sky objects. Exposure times are directly
proportional to the square of the difference of the f-numbers. For example, compare the exposure times needed
at f/10 versus those needed at f/2. The difference in f-number from f/10 to f/2 is a factor of five f-stops. The square
of this difference (52) equals 25. In other words, imaging at f/2 requires 25 times shorter exposure times than
imaging at f/10.
Assuming a CCD chip with 7.4 micron pixels used with a NexStar 8 at f/10 (2000mm), the image scale would be:
Although less resolution than at f/10, This combination is ideal for deep sky imaging when a wider field and light
sensitivity are are important than high definition.
Fastar opens up the world of CCD imaging to the amateur astronomers. High-quality images may now be
obtained by casual imagers in a fraction of the time it once took, and for thousands of dollars less!
47
A
PAG E NU MBE R
4
Altazimuth
A telescope mounting with two axes: one
horizontal, the other vertical.
Aperture
The diameter of the main optical element
(objective) of a telescope.
3
Apparent Field
The angular size of the light cone covered by an
eyepiece.
Arcsecond
An angular measurement equal to 1/1,296,000th
of a circle.
Astigmatism
A lens aberration that elongates images.
Axis
The straight line around which something rotates.
2
Azimuth
The angular measure of the distance around the
horizon measured from North clockwise towards
the East.
Barlow
A type of lens that increases the focal length of a
telescope. Barlow lenses are rated by the amount
of increase. For example: a 2x Barlow doubles the
focal length.
1
Cassegrain
A type of telescope design where light is reflected
from a main concave mirror to a smaller,
secondary mirror and back through a hole in the
center of the primary to an eyepiece. The
Schmidt-Cassegrain telescope has spherical mirrors
and a corrector lens at the front to correct for
spherical aberration. A Classical Cassegrain is a
special case where the primary is a Parabolic
mirror and the secondary is a hyperbolic mirror.
48
Catadioptric Telescope
A type of telescope design that uses the elements
of a reflecting and refracting telescope.
D
Glossary
1
Achromat
A type of lens design that uses two or more
different lens elements to compensate for
chromatic aberration.
C
B
CCD
Charge-Coupled Device, the light sensitive
electronic device used in digital cameras.
Celestial Equator
The circle that is a projection into the sky of the
Earth’s equator half way between the North and
South Poles.
Collimation
The proper alignment of the optical elements in a
telescope. Collimation is critical for achieving
optimum results. Poor collimation will result in
optical aberrations and distorted images. Not only
is the alignment of the optical elements important
but even more important is the alignment of the
optics with the mechanical tube-this is called
opto/mechanical alignment.
Chromatic Aberration
An optical aberration occurring when light passes
through a glass lens, the different color
components do not focus at the same place. This
is called chromatic aberration. Reflecting
telescopes are free of chromatic aberration.
Coma
An aberration of short focal length telescopes that
cause star images to look elongated or flared to
one side.
Contrast
The apparent difference in brightness between
light and dark areas of an image.
Constellation
Groupings of stars that make recognizable
patterns in the sky. The Greeks originally
recognized 48 constellations. In the 17th century,
40 more were identified.
Corrector
A lens placed at the front of a catadioptric
telescope to correct for spherical aberration.
Dawes Limit
The smallest angular distance between two objects
a telescope can resolve. The theoretical Dawes
Limit, in arcseconds, of a telescope is
approximately12 divided by the aperture in
centimeters (a=12/d) where “a” is in arcseconds
and “d” is in centimeters.
Declination
Also known as “DEC” is the angular distance North
and South of the Celestial Equator. Declination is
measured in degrees, minutes and seconds of arc.
The Declination at the Celestial Equator is 0
degrees. The Declination at the North Celestial
Pole is 90 degrees North.
Diffraction
The bending of light by any material.
Diffraction Limited
A diffraction limited telescope has aberrations
(optical errors) corrected to the point that residual
wavefront errors are substantially less than 1/4
wavelength of light at the focal point. In compound
optical systems, the individual components must
be better than 1/4 wavelength for the wavefront
error at the focal point to be at least 1/4 wavelength. As the wavefront number gets smaller
(1/8th or 1/10th wavelength), the optical quality
is progressively better.
Doublet
A lens made of two different kinds of glass.
Double Star
Two stars that rotate around each other. Also
called Binary Star.
Encoder
A mechanical device that produces pulses that can
be used to measure angular rotation. An absolute
encoder produces digital like codes that can
indicate the angular position of a rotating disk.
Equatorial
A telescope mounting with two axes: one parallel
to the Earth’s axis of rotation, the other
perpendicular to the first.
Equatorial Wedge
A device for tilting an altazimuth mount so that
one axis is parallel to the Earth’s axis making the
mount an equatorial mount.
Eye Relief
The viewing distance from an eyepiece to your eye
to see the best image.
Eyepiece
A magnifier used to visually look at the image
formed by the objective of a telescope. Also called
an Ocular.
Eyepiece Projection
The procedure of placing an eyepiece between
the objective of a telescope and a camera to
increase the photographic magnification.
Exit Pupil
The exit pupil of a telescope is the circular beam
of light that leaves the eyepiece being used and
is measured in mm. To calculate exit pupil, divide
the aperture (in mm) by the power of the eyepiece
being used. For example, an 8” aperture telescope
(203mm) used with a 20mm eyepiece is working
at 102 power and has an exit pupil of 2mm
(203/102 = 2mm).
Field of View
The amount of sky that you can view through a
telescope is called the real (true) field of view and
is measured in degrees of arc (angular field). The
larger the field of view, the larger the area of the
sky you can see. Angular field of view is calculated
by dividing the power being used into the apparent
field of view (in degrees) of the eyepiece being
used. For example, if you were using an eyepiece
with a 50 degree apparent field, and the power of
the telescope with this eyepiece was 100x, then the
field of view would be 0.5 degrees (50/100 = 0.5).
Finderscope
A low power telescope mounted to the side of a
higher-powered telescope. A special design of
finderscope employs a red light projected visually
onto the dark sky without magnification. Both
are used to locate objects more easily.
First Surface Mirror
A mirror where the shiny reflecting material is
deposited on the front of the mirror material
(usually glass). All astronomical mirrors are first
surface mirrors.
Focal Ratio
The ratio of the focal length to the diameter of
an optical system. It is found by dividing the focal
length of the system by the diameter of the
primary light gathering element of the system.
For example, a 10” telescope with a 100” focal
length is said to be an f/10 system (100/10). The
lower the focal ratio, the “faster” (and therefore
brighter) the image.
Image Scale
The amount of sky covered by a single pixel
measured in arcseconds. The formula for Image
Scale in arcseconds = (205 x Pixel Size in Microns)
/ (Telescope Focal Length in mm).
A
Light Year
The distance light travels in one year. Light travels
at the speed of about 186,000 miles per second. A
Light Year is approximately 6,000,000,000,000 (six
trillion) miles in distance. (The exact speed of light
in a vacuum is 299,792,458 meters per second or
186,282.02 miles per second.)
greater change than the unit difference. For
example: a star with a magnitude of 4.0 is 39.9
times as bright as a star with a magnitude of 0.
The faintest stars visible to the unaided eye are
about magnitude 6. Stars have two magnitudes:
actual and apparent.
Longitude
The distance on the Earth’s surface measured in
degrees, minutes and seconds of arc measured
East and West of Greenwich, England.
Near Focus
This is the nearest distance you can focus the
telescope visually or photographically for close
terrestrial work.
Maksutov
A type of telescope that uses a primary mirror and
a corrector lens in front. The corrector lens has a
silver spot in the center of the inside surface
(facing the primary) that functions as a secondary
mirror. All surfaces of a Maksutov telescope are
spherical.
Newtonian
A type of telescope that uses a single concave
(parabolic) mirror.
Magnification
The characteristic of an optical system to make
things look larger. Magnification is calculated by
the formula:
For a telescope with a focal length of 2000mm
and an eyepiece with a focal length of 25mm, the
formula becomes:
Magnification = 2000 / 25
Magnification = 40
Things viewed through this telescope / eyepiece
combination will look forty times larger than
when seen with the unaided eye.
Parabolic
A parabola is a plane curve generated by all points
equidistant from a point and a line. Rotating a
parabola around its axis generates a parabolic
shaped surface. Parabolic mirrors are used in
Newtonian and Classical Cassegrain telescopes.
Parabolic mirrors with focal lengths appropriate
for a telescope are slightly flatter in shape than a
spherical surface of the same focal length. This
difference eliminates spherical aberration present
in spherical mirrors.
Parfocal
The mechanical design of some eyepieces so the
image remains in focus between different
eyepieces of different focal lengths.
Prime Focus
The point where the image is formed by the
objective of a telescope.
Prism
A triangular optical device that can separate white
light into the colors of the rainbow. When used at
the correct angle, a right angle prism can be used
as a mirror.
Reflector
A type of telescope using a mirror as the objective
or primary optical element to collect light.
Refractor
A type of telescope using a lens as the objective or
primary optical element to collect light.
Resolution
The ability of a telescope, film, CCD or other
device to render detail. The higher the resolution,
the finer the detail.
Reticle
An optical device placed at the focus of an
eyepiece. A reticle is usually etched with a design
such as a cross that is used to observe the position
of an object in the field of view.
Right Ascension
Also known as “RA,” is the angular distance,
measured in hours, minutes and seconds, East of
the First Point of Aries. On the Celestial Equator,
hour markings would appear every 15º increasing
to the East. At the Meridian, as the sky sphere
appears to rotate to the West, the RA markings
would increase like the time display on a digital
clock. The RA at the Meridian is known as the
Local Sidereal Time.
Seeing
“Seeing” is the term astronomers use to describe
the sky’s atmospheric conditions. The atmosphere
is in continual motion with changing
temperatures, air currents, weather fronts and
dust particles. These factors cause the star images
to twinkle. If the stars are twinkling considerably
we have “poor” seeing conditions and when the
star images are steady we have “good” seeing
conditions. Poor seeing is most noticeable when
observing planets and the moon, whereas deep
sky objects such as nebulae and galaxies are less
affected by poor seeing conditions. On deep sky
objects, the most important factor is the
transparency of the atmosphere (a measure of
how dark the sky is on a given night-determined
by clouds, dust, haze and light pollution). Seeing
conditions and transparency will vary widely from
site to site, from season to season and from night
to night.
Setting Circles
Dials for right ascension and declination that
allow you to locate celestial objects easily from
their coordinates as listed in star charts. For
setting circles to work effectively, the telescope
must be equatorially mounted and polar aligned.
Slewing
The practice of moving a telescope in one or both
axes, under power of a motor.
T-mount
A universal-threaded adapter used to connect
many different brands of 35mm single lens reflex
film cameras to a telescope. A T-Adapter specific
to the camera has the same “T” thread. The two
together adapt a specific camera to a specific
telescope.
Vignetting
Darkened edges of an image caused by lower
amounts of light reaching the image plane far
from the center of view.
4
Magnitude
The measure of the brightness of a celestial object.
The magnitude scale starts at zero (0) and extends
in both directions (negative and positive). It is a
logarithm scale (on a special base number) which
means each successive number represents a
Optical Axis
A line through the center of an optical system
perpendicular to a tangent.
Porro Prism
A prism that inverts the image entering it. Since
the image formed by a telescope is upside down,
using a porro prism makes it appear upright.
Schmidt
A corrector lens invented by Bernhard Schmidt
placed in front of a mirror telescope. It improves
the photographic speed, reduces physical length,
and widens and flattens the field of view. When
used in a Schmidt-Cassegrain telescope, it also
corrects for spherical aberration.
3
Focal Length of
Primary Mirror or Lens
Magnification = ________________________
Focal Length of Eyepiece
North Celestial Pole
The point in the sky that is the projection of the
Earth’s axis of rotation. The North Celestial Pole is
0º 51’ 55” away from the North Star (Polaris or
Alpha Ursae Minoris). Said another way, Polaris is
nearly two full moon diameters away from the
North Celestial Pole.
Plössl
A type of eyepiece design providing excellent field
of view, flatness of field and color correction.
D
2
Limiting Magnitude
The faintest object visible in a given telescope.
Messier Catalog
A catalog of 103 nebulae, star clusters and
galaxies documented in 1781. Seven more were
added later bringing the total to 110. All of the
Messier objects (designated by an “M” and a
number e.g. M81) are visible with a 3” or larger
telescope. Many are visible using binoculars and
other smaller telescopes.
C
1
Latitude
The distance of the Earth’s surface measured in
degrees, minutes and seconds of arc North and
South of the Equator.
B
A
B
C
D
1
2
Object: Rosette Nebula
Instrument: CGE1400 Fastar
3
Object: M27
Instrument: C14
Photographer: Ted Inoue
Object: Veil Nebula
Instrument: C14 Fastar
Photographer: Jim Riffle
Object: Running Man Nebula
Instrument: C14
Photographer: Rick Thurmond
©2003 Celestron
93895-03
NexStar, SkyMaster, and StarBright are registered trademarks of Celestron. Product design and specification subject to change.
4
2835 Columbia Street, Torrance, CA 90503, USA
310-328-9560 phone / 310-212-5835 fax
www.celestron.com

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