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This is the Griffith Observatory Sky Report through October 18, 2017. Here’s what’s happening in the skies of southern California.
The planet Saturn, in the constellation Ophiuchus the Snake Bearer, is visible briefly in the evening between about 6:45 p.m., when the sky becomes dark enough to first see it the southwest sky, and until it sets in the west-southwest at about 9:30 p.m. A telescope is needed to see Saturn’s magnificent ring system. The rings show their maximum tilt for the next 15 years, 26.996 degrees from edge-on, on the 16th.
The waning moon is last quarter at dawn on the 12th. It rises at 11:42 p.m. on the 11th, and at 5:51 a.m. on the 18th. On the 17th, the moon’s slender crescent appears below the orange-hued planet Mars and above the brilliant white planet Venus.
On Sunday morning, the 15th, the bright star Regulus, in Leo the Lion, will appear from behind the dark upper limb of the moon at 3:12 a.m. This happens shortly after moonrise, and to see it you must have a clear eastern horizon as the moon’s elevation is then only four degrees. Binoculars will help you to observe Regulus as it flashes suddenly into view. The moon’s passage in front of Regulus, called a stellar occultation, is visible before sunrise from nearly all of the United States, much of Mexico, and Cuba, but the time at which it occurs depends on the location. General information about the occultation is provided on the EarthSky Website.
Comet C/2017 O1 ASSASN, named for its electronic discoverer, the All-Sky Automated Survey for Supernovae, is visible before moonrise through small telescopes. It currently glows at magnitude 8.3, and it will be closest to earth on the 17th when it is about 67 million miles away. It travels north against the stars and crosses from the constellation Perseus the Hero into the adjacent Camelopardalis the Girraffe on the 16th. Generate a finder chart for the comet by using the In-The-Sky.org website.
The International Space Station passes high over Los Angeles on the evening of Saturday, October 14. The brilliant ISS will appear above the northwest horizon at 7:35 p.m., and will climb until it is 64 degrees high in the northeast at 7:38 p.m. Half a minute later, it vanishes into earth’s shadow in the east and still 52 degrees high.
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, October 21st.
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From Griffith Observatory, I’m Anthony Cook, and I can be reached at griffithobserver@gmail.com.