The nights are getting longer and the fall constellations are arriving in the northern hemisphere's sky.
Comet Garradd and Comet Elenin
Two comets are visible in September's sky but they will take a little work to spot. Comet Elenin, the brighter of the two, is in the more challenging location. Comet Elenin will shine at around magnitude 5.8 but will be low in the west after sunset, and the fading sunlight may drown out your chance to catch it. Look on September 22 and 23 when Comet Elenin is just to Porrima's lower right. Porrima is an easy star to find if you have been tracking Saturn all summer. Saturn has been beside Porrima in Virgo for much of the time. Another way to find Porrima is first to find Virgo's brightest star Spica and then look to Spica's right to find the fainter Porrima.
Comet Garradd is passing out of the Summer Triangle in September and headed for Hercules. On September 3, catch Comet Garradd with binoculars or a small telescope as it resides near the Coathanger Cluster in Vulpecula. Comet Garradd will be a bit dimmer than Elenin, but because of its location it should be easier to nab.
Planets for September 2011
The planets are becoming more scarce in the evening sky in September. Saturn, which has been a great telescopic target all summer, is now sinking in the west at sunset. It can still be seen at the beginning of the month in the constellation Virgo. Jupiter is rising in the east later in the evening in the constellation Aries.
For early risers, Mars is in the east at dawn in the constellation Gemini. Mercury is also visible at dawn early in the month. On September 9, Mercury will be close to the star Regulus in Leo.
The Moon in September
September's full moon will occur at 5:27 a.m. EDT on Monday, September 12. This September's full moon is the well-known Harvest Moon. By nightfall on the 12th, the moon will already be rising just before the sun sets.
On September 15 and 16, the moon will keep close company with Jupiter. On September 17, find the moon close to the Pleiades star cluster. As a challenge, on September 28, look for a crescent moon low in the west after sunset with Venus to its right.
September Equinox
The northern hemisphere's fall equinox and southern hemisphere's spring equinox occur on September 23. At 5:05 a.m. EDT, the first day of fall is when the sun will rise directly in the east and set directly in the west. Because of the tilt in Earth's axis as it orbits the sun, on the equinoxes it appears that the sun crosses the celestial equator. From this point until the next equinox, the northern hemisphere will experience more hours of darkness than daylight.
Source: Celestron's The Sky software
Kelly Whitt - I have been a professional writer for more than a decade, covering many topics from science-based articles to do-it-yourself home ...
