Astronomy Club of Asheville June 2016 Sky Events

Astronomy Club of Asheville
June 2016 Sky Events
The Planets this Month - page 2
Planet Highlights - page 7
Moon Phases - page 10
June 20th - the Summer Solstice - page 11
4 Celestial Neighbors on
the Virgo/Corvus Border - page 13
www.AstroAsheville.org
Astronomy Club of Asheville
June 2016 Sky Events – the Planets
 June 2016 provides 3 planets that will brighten the early
evening skies. Jupiter will dominate the southwest while Mars
and Saturn will reign in the southeast.
 Against the background of the constellation Leo, Jupiter is
best viewed this month well before midnight, while it is still
high in the sky.
 Mars reached opposition (opposite the Sun from Earth) on
May 22nd; so it’s nearest to Earth for the year, making this
month an ideal time to observe its planetary disk.
 At a distance of just 0.52 AUs (astronomical units), this is the
closest opposition of Mars in 11 years. It’s just 48 million miles
away (about half the Earth-Sun distance), and it shines at an
average magnitude of -1.7 almost as bright as Jupiter!
 Located in the constellation Libra this month, this is a great
time to look for telescopic details on the red planet.
Astronomy Club of Asheville
June 2016 Sky Events – the Planets
The Moon Joins the Planet Jupiter
On the evenings of June 9 - 11, the
waxing Moon joins the bright planet
Jupiter in the constellation Leo.
The two solar system objects will
appear closest on the night of June 11th
when they are separated by about 6°
and located about 46° above the
horizon.
Although these 2 celestial objects
appear close in our 2-dimensional
view, Jupiter is some 484 million miles
behind the Moon!
Image courtesy of
Sky & Telescope
Astronomy Club of Asheville
June 2016 Sky Events – the Planets
 The planet Saturn can be found all night this month – rising at
dusk on June 1st and at sunset, well above the southeast
horizon, by month-end. Saturn reaches opposition - closest
position to Earth for the year - on June 3rd. So this month it
will be at its brightest and best observing position for the year.
 Saturn’s rings are currently tilted a wide 26˚ toward us (near
their maximum angle of 27˚); so the rings will look spectacular
in the telescope eyepiece. You will be looking at Saturn’s rings
from above on their northern face; not until the year 2025 will
you be able to catch a glimpse of the rings from the planet’s
southern face!
 Find Saturn located within the boundaries of the constellation
Ophiuchus, the Serpent Holder, all month.
Astronomy Club of Asheville
June 2016 Sky Events – the Planets
Saturn, Mars and the Full Moon
After dark on the nights of June 16-18,
look SE to locate the planets Saturn and
Mars with the Full Moon.
Mars reached opposition on May 22nd, and
Saturn reached opposition on June 3rd. So
both planets will be near their closest
approach to Earth for the year, appearing
very bright, and at their largest in
telescopes for the year as well.
The bright red giant star Antares in
Scorpius will also shine with an orange
tint. It’s name (from the ancient Greek)
literally means “rival of Mars” (in orange
brightness). Mars is the Roman name for
the Greek war god, Ares.
Image courtesy of
Sky & Telescope
Astronomy Club of Asheville
June 2016 Sky Events – the Planets
 Venus reaches superior conjunction (on the opposite side
of the Sun from Earth) on June 6th; so it’s lost in the Sun’s
glare and unobservable this month.
 Mercury reaches greatest elongation west of the Sun
(24˚) on June 5th. Because of the low angle of the ecliptic, it
will be challenging to locate Mercury in the dawn skies this
month.
 Uranus and Neptune can be found in the pre-dawn skies this
month in the constellations Pisces and Aquarius respectively.
You will need binoculars or a telescope to locate and observe
these two distant planets.
Astronomy Club of Asheville
June 2016 Planet Highlights
Planet
Avg.
ConstellaDistance tion(s)
from
Earth
Avg.
Avg.
Diameter Magin arc
nitude
seconds
Comments
Page 1 of 3
Mercury 1.0
AUs
Aries,
Taurus &
Gemini
7.6
-0.3
Reaches greatest
elongation west
(24º) on June 5th
Venus
1.7
AUs
Taurus &
Gemini
9.6
-3.9
Reaches superior
conjunction on
June 6th
Mars
0.5
AUs
Libra
17.6
-1.7
Shining brightly
in the night sky
all month
Astronomy Club of Asheville
June 2016 Planet Highlights
Avg.
Distance
from
Earth
Constellation(s)
Jupiter
5.5 AUs
Saturn
Uranus
Planet
Avg.
Diameter
in arc
seconds
Avg.
Magnitude
Comments
Leo
35.9
-2.0
View it before
midnight this
month
9.1 AUs
Ophiuchus
18.3
0.0
At opposition
with Earth on
June 3rd
20 AUs
Pisces
3.5
5.9
Find it in the
pre-dawn sky
this month
Page 2 of 3
Astronomy Club of Asheville
June 2016 Planet Highlights
Planet
Avg.
ConstellaDistance tion(s)
from
Earth
Neptune 30 AUs
Aquarius
Avg.
Avg.
Diameter Magin arc
nitude
seconds
2.3
7.9
Comments
Page 3 of 3
Find it in the
pre-dawn sky
this month
Astronomy Club of Asheville
The Moon – June 2016
New Moon
4th
11:01 p.m.
First Quarter
12th
4:10 a.m.
Full Moon**
20th
7:04 a.m.
Last Quarter
27th
2:20 p.m.
** The “Strawberry Moon”
Unless otherwise indicated, all times are EDT
Astronomy Club of Asheville
June 2016 Sky Events
June 20th, 2016 Summer Solstice
 The northern hemisphere’s summer solstice occurs on Monday,
June 20th at 6:34 p.m. EDT.
 It’s the longest day (and shortest night) of the year in the
northern hemisphere.
 The Sun’s position on the summer solstice in the Asheville area
reaches 2 extremes in altitude and azimuth (the following
values are rounded):
1. First the Sun rises 30° north of east and sets 30° north of west
on the summer solstice, compared to 30° south of east and 30°
south of west on the winter solstice; that’s a 60° swing.
2. Next the Sun rises 78° above the horizon at high solar noon on
the summer solstice, compared to only 31° on the winter
solstice; that’s a 47° swing (Earth’s 23½° axial tilt times 2).
Astronomy Club of Asheville
June 2016 Sky Events
June 20th, 2016 Summer Solstice
 Translation: At the summer solstice the Sun takes not only a
longer path across the sky but also a much higher path across
the sky, yielding a much longer daylight period, with the Sun’s
radiation at a more intense angle.
Astronomy Club of Asheville
June 2016 Highlight:
4 Celestial Neighbors on the Virgo/Corvus Border
 Located on the border of the constellations Virgo and
Corvus, the famous Sombrero Galaxy (M104) is often
observed in small telescopes, and it is one of the
brightest galaxies in the sky as seen from Earth.
 But mostly overlooked are 3 other wonderful celestial
objects that are all located within 1½° of the
Sombrero Galaxy.
 These wonders include 2 remarkable asterisms (star
cluster imposters), the Jaws and the Stargate, and a
most striking binary star, ∑1669.
Astronomy Club of Asheville
June 2016 Highlight:
 M 104 (the
Sombrero galaxy) is
a bright edge-on spiral
galaxy with a most
pronounced central
bulge and dark dust
lanes.
 It is located some 30
million light years away
in the constellation
Virgo, but it is not a
member of the more
distant Virgo galaxy
cluster.
4 Celestial Neighbors on
the Virgo/Corvus Border
This image shows M104 in the lower left
along with the asterism cluster of stars,
know by the moniker “the Jaws”, to the mid
and upper right.
Astronomy Club of Asheville
June 2016 Highlight
4 Celestial Neighbors on the Virgo/Corvus Border
 The Jaws is an asterism
of 8th to 10th magnitude
stars located very near the
Sombrero Galaxy in the
constellation Virgo.
 It’s an asterism, and not a
true star cluster, because
the stars are located at
significantly different
distances from us.
 This striking chance alignment of stars appeared, to at least one
observer, like the jaws of a shark.
Astronomy Club of Asheville
4 Celestial Neighbors on
June 2016 Highlight:
the Virgo/Corvus Border
 The Stargate is another
asterism, and it consists of 6th to
12th magnitude stars.
 It’s an asterism, and not a true
star cluster, because the stars
are located at significantly
different distances from us.
 Located in the constellation
Corvus, this group of stars is
most impressive for its shape –
a small triangle inside a larger
one. Larger aperture telescopes
are needed to split the dim star
at the lower-left corner of the
inside triangle.
Astronomy Club of Asheville
June 2016 Highlight:
 Binary star ∑1669 is a close
pair (5.3 seconds of arc
separation) of yellow stars that
are nearly a perfect match.
 Located in the constellation
Libra, this pair of stars is a true
binary – the 2 stars are
gravitationally bound and orbit
each other.
 Shining at magnitude 5.9, Struve
(∑) 1669 is some 278 light years
away, and it is easily split at high
power in small telescopes.
4 Celestial Neighbors on
the Virgo/Corvus Border
The Sombrero Galaxy
June 2016 Highlight:
and Neighbors
Astronomy Club of Asheville
 The two asterisms (the
Jaws and the Stargate)
along with binary star
Struve 1669 are all
located within 1½° of
the Sombrero Galaxy,
despite the huge
distances that actually
separate them.
 All 4 objects can be
found along the
border of the
constellations Corvus
and Virgo.
Astronomy Club of Asheville
June 2016 Highlight:
4 Celestial Neighbors on the Virgo/Corvus Border
Object
Object Type
RA
DEC
Magnitude
Distance
In Light
Years
M104
“Sombrero”
Edge-on spiral
galaxy
12h 41m
-11° 42’
8.3
30 million
The Stargate
STF 1659
Optical star
cluster asterism
12h 36m
-12° 06’
6 to 12
285 to
486 &
more
The Jaws
Optical star
cluster asterism
12h 39m
-11° 33’
8 to 10
75 to
1,400
∑1669
(HIP # 61910)
Binary star
12h 41m
-13° 03’
5.9/5.9
Sep. 5.3”
278
End