Griffith Observatory Sky Report for the week ending Wednesday, September 5, 2012

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This is the Griffith Observatory Sky Report for the week ending Wednesday, September 5, 2012. Here is what’s happening in the skies of Southern California:

The moon dominates most of the night sky this week. The phase of the moon waxes from gibbous until full moon occurs at 6:58 a.m., P.D.T. on Friday, August 31. Because this is the second full moon in the calendar month, something that usually happens only every two or three years, it is said to be a “blue moon,” although there is nothing unusual about its appearance. For residents of Los Angeles, the moon will appear nearly full when it sets at 6:34 a.m. Friday morning and again, a little over 12 hours later, when it rises at 7:13 p.m. Friday night. On the following nights through Tuesday, the moon will be in waning gibbous phase, and rises an average of 44 minutes later each successive night.

The trio of bright objects that includes the planets Mars and Saturn and the bright star Spica of Virgo the Maiden, can still be spotted low in the west-southwest during evening twilight. Spica is the lowest of the three, with Saturn above it, and Mars to the upper left of Saturn and Spica. These objects are best seen between 8:00 and 8:45 p.m.

The brilliant planet Jupiter is in Taurus the Bull and is noticeable in the east by 12:30 a.m. At dawn, Jupiter is high in the southeast. Use a telescope to observe the tiny shadow of Jupiter’s Galilean satellite, Io, cross the disk on the morning of September 4, an event known as a shadow transit.

The brightest planet, Venus, rises in the east-northeast at 3:00 a.m. Venus is between Jupiter and the eastern horizon at dawn. A telescope will show the planet’s gibbous phase.

Los Angeles viewers can see the International Space Station cross the western sky on Wednesday, September 29. Between 8:09 and 8:16 p.m., P.D.T., the bright satellite will move from the west-northwest to the east-northeast horizon and will reach an apex of 39 degrees in the southwest at 8:13 p.m., moments after passing below the bright star Arcturus in Boötes the Herdsman.

Free views of the sun during the day and of the moon, planets, and other celestial objects at night, are available to the public in clear weather six days a week (Tuesday-Sunday) through Griffith Observatory’s telescopes before 9:30 p.m. Check our website for our schedule. The next Griffith Observatory public star party, hosted by Los Angeles Astronomical Society, the Sidewalk Astronomers, and the Planetary Society is scheduled for Saturday, September 22.

From Griffith Observatory, I’m Anthony Cook, and I can be reached at