The Night Sky This Month – September 2012

Posted by Brian Ventrudo

Spring comes this month to the southern hemisphere and autumn comes to the north, and there’s a change afoot in the sky.  The brilliant star clouds along the spine of the Milky Way still linger.  But sparser constellations also come into view: Pegasus and Andromeda in the north, and Sculptor, Tucana, and Pavo in the south. And there are planets… Saturn and Mars fading in the southwest after sunset, and brilliant Venus and Jupiter visible well before sunrise.  Even Uranus takes a turn in the spotlight this month.  The 7th planet rises opposite the Sun on September 29, and passes a 6th-magnitude star a week before, making the planet easy to find and see. Here’s what to look for in the night sky this month…

* * * Tour the Night Sky With a Small Telescope * * *

“What To See In A Small Telescope” takes you to nearly 100 deep-sky sights in the night sky from July through September. Includes maps and instructions to find every object, and tips on what to look for.   Now available from One-Minute Astronomer.  Click here to learn more…

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Note: You can access a free real-time star chart by clicking here.  You can configure this chart to your own location.  Just make sure you have Javascript enabled in your browser.

8 Sept.  Last Quarter Moon, 15:15 UT.

8 Sept.  Look for Jupiter above the last-quarter Moon from near midnight to dawn.  The big planet brightens this month to magnitude -2.5 and grows to an impressive apparent size of 43″.  The planet is 90º west of the Sun, so its moons cast maximally displaced shadows on the face of the planet.

12 Sept.  Look for brilliant Venus near the waning crescent Moon about an hour before sunrise.  The bright planet dominates the eastern sky this month, far outshining any other object in the sky except for the Sun and Moon.

16 Sept.  New Moon, 02:11 UT.

15-30 Sept.  If you have very dark and clear sky, look for the zodiacal light in the eastern sky before sunrise.  It looks like large a glowing wedge thrusting out from the horizon.  This year, the wedge of the zodiacal light points directly at Venus.

18 Sept.  The waxing crescent Moon nears Saturn and Mars on Sept. 18-19.  Look for the spectacle in the southwestern sky after sunset.

22 Sept.  Spring begins in the southern hemisphere and autumn begins in the north at 14:49 UT as the Sun moves south across the celestial equator.

22 Sept.  First Quarter Moon, 19:41 UT.

22-23 Sept.  The planet Uranus passes within 2 arc-minutes of the 6th-magnitude star 44 Piscium (see image below).  Star and planet have roughly the same brightness.  But look for the colour difference between the two.  The star is yellow-white, while the planet is greenish or aquamarine.  The planet is seen best after midnight, and is visible in both northern and southern hemispheres.

Uranus on September 22, 2012. The planet lies within 2' of the 6th-magnitude star 44 Piscium. Click to enlarge.