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This is the Griffith Observatory Sky Report through January 18th, 2017. Here’s what’s happening in the skies of southern California.
Shortly after sunset, the brightest planet, Venus, is the eye-catching white object high in the southwest sky. As the sky darkens more, the orange planet Mars becomes visible to the upper left of Venus. Although Mars is currently on the far side of its orbit with respect to the sun and too far away to show interesting detail through a telescope, Venus is approaching earth and will allow observers to watch through telescopes as the planet changes phase from gibbous to crescent between the 11th and 18th. Venus will also guide observers to the faintest planet, Neptune, on Thursday the 12th. On that evening, Neptune will be located only 24 arcminutes south of Venus, close enough that both planets should fit into the same eyepiece field of view at a magnification 100-power or less. The half-lit disk of Venus appears 11 times wider and 14,000 times brighter than the ghostly blue spot of Neptune.
Starting about 45 minutes after sunset, Mars and Venus can also be used to guide you to a comet that is becoming hard to see in the evening twilight. Comet 45P/Honda-Mrkos-Padjusakova may be visible through binoculars at 6th magnitude, close to the horizon, and along the imaginary line extended through Venus from Mars. The comet should be brighter and much easier to see beginning in mid-February when it passes high overhead at night. The Free Star Charts website has information about locating the comet.
Another binocular challenge this month is the asteroid Vesta. Vesta is at opposition with the sun on 17th, meaning that is visible nearly all night long. It is also at its closest to the earth, and is bright enough to see with ease through binoculars. It is in the dim constellation Cancer the Crab, between Cancer’s “Beehive” star cluster, M44, and the bright stars Castor and Pollux of the neighboring constellation Gemini the Twins. The asteroid can be identified with a chart also provided on the Free Star Charts website.
The moon is full on the morning of the 12th, and afterwards is waning gibbous through the 18th. The time of moonrise advances from 4:41 p.m. on the 11th to 11:42 p.m. on the 18th.
The planets Jupiter, Saturn, and Mercury are visible before sunrise. Jupiter is in the constellation Virgo the Maiden, close to Virgo’s bright star Spica, and rises above the eastern horizon at about midnight. At 6:00 a.m., Jupiter crosses the meridian, high in the south. At the same time, look for three bright objects in the southeast sky that form a diagonal line to the horizon. From upper right to lower left, they are the star Antares of Scorpius the Scorpion, the ringed planet Saturn, and the innermost planet, Mercury.
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, February 4th.
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.