CVAS Monthly Sky Calendar - September 2010

Home

Indian Hill Observatory & Map

Updated September 2, 2010

Venus - is the "evening star" until October.  Look for it 14 degrees up in the SW at sunset early this month and only 7 degrees up by month's end.  Venus will be magnitude -4.5 and have a disc that increases in diameter from 28 to 44 arc-seconds.  The crescent shape of Venus may even be seen in binoculars by month's end.

Here are some recent images of Venus made by amateur astronomers:

http://alpo-astronomy.org/gallery/main.php?g2_itemId=1566

http://www.astrofotografie.nl/Venus.htm

Saturn - located in Virgo.  The ringed planet can be seen only 5 degrees up in the WSW a half-hour after sunset early in September.  Saturn will be magnitude 1.1 with an apparent diameter of 16 arc-seconds.  The rings will be 35 arc-seconds across with a tilt of 5 degrees to our line-of-sight.  Saturn passes through conjunction with the Sun on October 1st and will become visible in the morning sky a few weeks later.

Some excellent images of Saturn and its transiting moons can be seen here:

http://astro.christone.net/saturn/index.htm

The Cassini spacecraft continues its observation of Saturn and its many moons and rings.  For the latest images from Cassini, see:

http://saturn.jpl.nasa.gov/home/index.cfm

Mars - located in Virgo and Libra.  Mars is only 9 degrees above the WSW horizon a half-hour after sunset around mid-month.  The "red planet" is magnitude 1.5 and will have a diameter of 4.2 arc-seconds.  It will be difficult to see any surface detail due to the planet's small size and low altitude.  Mars can be seen 4 to 7 degrees to the upper right of Venus during September.

Recent images of Mars by amateurs can be seen here:

For an even better view of Mars, check out the view from the Mars Rovers:

http://marsrovers.jpl.nasa.gov/home/index.html

Pluto - located in Sagittarius.  The best time to see this "dwarf planet" is around 9:00 pm EDT at mid-month when it will be 30 degrees up in the south.  An 8 inch or larger telescope and dark skies will be needed to see Pluto's faint magnitude 14.2 light.  Due to Pluto's small size (0.1 arc-seconds), it will look like a faint star and not a planet.  To identify Pluto correctly, it may be necessary to observe it on a second night to check for motion.

A finder chart for Pluto can be found here:

http://www.skyandtelescope.com/observing/objects/planets/89002802.html

Neptune - located in Capricornus.  Neptune can best be seen around 12 am EDT at mid-month.  Look for it 35 degrees up in the south.  Neptune will be magnitude 7.8 and have a tiny 2.4 arc-second pale blue disc. 

Observers with 8 inch and larger scopes can also look for Neptune's largest moon, Triton.  Triton is magnitude 13.5 and is located 12 to 16 arc-seconds away from Neptune.

A finder chart for Neptune can be found here:

http://www.skyandtelescope.com/observing/highlights/85530917.html

Jupiter - located in Pisces.  The "king of the planets" passes through opposition on September 21st and is up all night.  It will be 47 degrees up in the south by 2 am.  Jupiter will be magnitude -2.9 and have a diameter of 49 to 50 arc-seconds. 

The SEB of Jupiter has faded.  This belt normally appears orange or red but now appears white.  In smaller telescopes, Jupiter appears to have only one major belt.  This makes the GRS easier to see, since it currently has an orange-red appearance.

Jupiter's Great Red Spot, a large anti-cyclone, can be seen centered on the planet's disc at the following times (EDT): 

Additional times for viewing the Great Red Spot can be found here: 

http://skytonight.com/observing/objects/planets/3304091.html

Some excellent images of Jupiter can be seen here:

http://astro.christone.net/jupiter/index.htm

A guide for making visual observations of Jupiter can be found here: 

http://chagrinvalleyastronomy.org/Observing Jupiter.ppt

Uranus - located in Pisces.  Uranus passes through opposition on the night of September 21/22 and can best be seen around 2 am at mid-month, when it will be 47 degrees up in the south.  Look for it within 1 degree of Jupiter for a week before and after the 19th.  Uranus will be magnitude 5.7 and have a tiny 3.7 arc-second pale green disc.

A finder chart for Uranus can be found here:

http://www.skyandtelescope.com/observing/highlights/85530917.html

At least four of Uranus' moons can be seen with larger amateur scopes.  These moons can be identified using this page:

http://www.skyandtelescope.com/observing/objects/javascript/3310476.html

Mercury - visible in the morning sky during mid to late September.  Look for it about 5 to 10 degrees up in the east, a half-hour before sunrise.  Mercury will range in brightness from magnitude 1.0 to -1.1.  The planet's disc will decrease from 8 to 6 arc-seconds in diameter while the phase changes from a crescent to gibbous.

Mercury received its first visit from a spacecraft in 33 years when the Messenger orbiter flew by in January, 2008.  For the latest images and other details, see:

http://messenger.jhuapl.edu/

Epsilon Aurigae - a unique eclipsing variable star, is just past the mid-point of its long-awaited eclipse.  This variable is a binary star where one companion eclipses the other once every 27 years.  During an eclipse, Epsilon drops in brightness from magnitude 2.9 to 3.8 and remains at 3.8 for over 1 year before slowly recovering.  The current eclipse will last until 2011.  During September, Epsilon can be seen from 12 to 6 am EDT (when it will be 20 to 70 degrees up in the NE).  The star is currently magnitude 3.7 or 3.8.  Epsilon will remain in total eclipse until January, 2011.

More information and finder charts for this variable star can be found here:

http://www.citizensky.org/

http://www.skyandtelescope.com/community/skyblog/observingblog/59057072.html

Special Photos:

August 7, 2005 Moon and Venus