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This is the Griffith Observatory Sky Report through August 2, 2017. Here’s what’s happening in the skies of southern California.
The innermost planet, Mercury should be visible in the west through the 28th, starting at about 8:40 p.m., when the sky is dark enough to see it. Mercury will then be about six degrees above the western horizon. Six degrees is an angle that is a little more than half as high your clenched fist appears when it is held out at arm’s length. Mercury outshines the bright star Regulus in Leo the Lion. On the 26th, Mercury appears two degrees to the left of Regulus, and on the 28th, you will see that the separation between the planet and star has nearly doubled.
At evening twilight, the planet Jupiter is the brilliant object that gleams in the southwest with a pale-yellow hue. The four largest moons of Jupiter and the planet’s striped cloud bands are visible through most telescopes. A telescope can allow you to see Jupiter’s famous Great Red Spot. The colorful and centuries-old oval storm on Jupiter will be visible to west coast observers at 9:00 p.m. on July 26th, 28th, 31st, and August 2nd. Jupiter sets in the west at about 11:15 p.m.
The ringed planet Saturn, bright and golden against the backdrop of fainter stars in the constellation Ophicuhus the Serpent-Bearer, crosses the meridian in the south at 9:45 p.m. Saturn’s spectacular rings are visible through telescopes, as are several of its many moons, the brightest and largest of which is Titan. Titan, which takes 15 days to orbit around Saturn, will appear about four ring diameters directly to the east of Saturn on July 29. If you’re not sure in what direction east appears in your telescope, just turn off your tracking and let the sky drift through your eyepiece. You will see Titan trailing behind the planet as the result of the earth’s rotation.
The brightest planet, Venus, rises above the east-northeast horizon at 3:08 a.m. Venus can still be seen at sunrise when it is 34 degrees above the eastern horizon.
The moon’s phase is waxing and changes from crescent to first quarter on the 30th, and afterwards is gibbous. It sets at 10:29 p.m. on July 26th and at 1:58 a.m. on August 2nd. The moon appears near Jupiter on July 28th and above Saturn on August 2nd.
If you have the equipment needed to safely photograph next month’s solar eclipse, you should consider removing the solar filters and practice your photography before hand on the moon. Problems of focusing your shots and of eliminating vibration from them are the same as they will be during the eclipse, and finding problems now will give you a chance to solve them before the eclipse occurs. Master astrophotographer Jerry Lodriguss has written a very useful article regarding eclipse photography.
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, July 29th.
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.