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This is the Griffith Observatory Sky Report through September 13, 2017. Here’s what’s happening in the skies of southern California.
The ringed planet Saturn, in the constellation Ophiuchus the Serpent Bearer, is best seen in the evening twilight when it is close to the southern meridian. Its beautiful ring system is a stunning sight through telescopes, and the planet is currently featured through the public telescopes at Griffith Observatory. In the next few weeks, however, Saturn will appear to drift in the sun’s direction and it will soon be lost in the twilight.
The planet Jupiter is already becoming hard to see in the evening twilight. At 7:30 p.m., it is only 13 degrees above the western horizon and it sets at about 8:45 p.m.
The moon is waning gibbous until it become last quarter on the 12th. Having past full moon on the morning of the 6th, the moon will rise later after sunset by a longer interval night by night. It rises at 7:45 p.m. on the 6th and at 11:54 p.m. on the 12th.
The brightest planet, Venus, rises in the east at 4:15 a.m., and is 27 degrees high at sunrise. About 30 minutes before sunrise, or at about 6:00 a.m., Venus will be useful in following other events unfolding in the sky at that time.
At 6:00 a.m., look about 1/3 the way up from between the eastern horizon and Venus to find the innermost planet, Mercury. Starting on the 7th, and then morning by morning through the 10th, Mercury will appear higher and closer to Leo the Lion’s bright star Regulus, with Regulus approaching Mercury from the lower left. On the 10th, the two objects will be closest together and separated by less than a degree, with Regulus above Mercury. After the 10th Regulus and Mercury appear farther apart. By the 12th, Mercury will appear between Regulus and the dimmer planet Mars. Use binoculars to see the orange tint of Mars.
The bright orange star Aldebaran in the constellation Taurus the Bull will be blocked by the moon between 4:34 a.m. and 5:50 a.m. on Tuesday, September 12, as seen from the Los Angeles area. This type of event is called an occultation. Because Aldebaran is 67 light years away and therefore appears point like even through a telescope, its disappearance and reappearance at the edge of the moon occurs with stunning brevity when viewed through optical aid. The occultation is visible before sunrise from Hawaii and the entire west coast of the U.S. including southern Alaska, but at times different from those at Los Angeles. The Web journal EarthSky lists the times when the occultation will occur from four representative locations within this zone.
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 through Griffith Observatory’s telescopes from Tuesday through Sunday, before 9:30 p.m. Check our website for the schedule. The next free public star party on the grounds of Griffith Observatory, hosted by the Los Angeles Astronomical Society, the Sidewalk Astronomers, and the Planetary Society, will take place on Saturday, September 30.
Follow the Sky Report on Twitter for updates of astronomy and space-related events.
From Griffith Observatory, I’m Anthony Cook, and I can be reached at griffithobserver@gmail.com.