Stars over Sisters

The lunar cycle for September opens with a waxing crescent phase until the fourth of the month when, first quarter occurs. At that time observers here on Earth will see the sun light the western half of the moon. The moon will continue to wax (brighten) until September 12, when the harvest moon will illuminate the entire night sky.

The full moon closest to the autumnal equinox (September 23) is called the harvest moon. This usually happens in September, but during some years it can be delayed until early October. From here the moon goes on the wane: last quarter on the 20th of the month; new on September 27.

Saturn disappears from the western sky by mid-month. The planet Jupiter, still in the constellation of Aries, rises at dusk and is by far the brightest object in the night sky. Venus can't be seen this month because it is too close to the sun. Early in the month Mercury makes a favorable appearance just above the eastern horizon at dawn. The earth is slowly closing the distance on Mars, but won't actually catch up to it until March 3, 2012. The Red Planet rises at about 2 a.m. this month.

A comet has been moving westward through the sky this summer as it approaches the inner solar system. Discovered by Australian Gordon Garradd in 2009, the comet is too dim to be seen without optical aid but can be detected in small backyard telescopes. The comet is expected to be at its brightest late in February of 2012, when it may become a naked eye object.

The flying snowball will be closest to the earth on March 5 when it approaches to within about 118 million miles. At that time it can be seen moving through the Little Dipper.

Three other known comets are currently falling toward the sun. One of them, C/2011 L4 (PANSTARRS), may become a prominent object in the spring of 2013.

If you would like to learn more about astronomy, come to the Sisters Astronomy Club's meetings at Sisters Park & Recreation District (SPRD.) They are held on the third Tuesday of every month. The next meeting will be September 20, starting at 7 p.m. The next Stars over Sisters star watch will be Friday, September 23, at SPRD beginning at 7:30 p.m.