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This is the Griffith Observatory Sky Report through December 9, 2015. Here’s what’s happening in the skies of southern California.
The brightest nighttime star, Sirius, in constellation Canis Major the Big Dog, first glitters in the southeast sky before 9:00 p.m. During the night Sirius slowly arcs upward and to the right, reaches its highest point while due south at about 1:45 a.m., and then descends into the southwest sky as the dawn approaches.
The three bright planets visible through the week ending on the 9th are all early morning objects. Jupiter, in the constellation Leo the Lion, is the second-brightest planet and is the first to rise above the eastern horizon shortly before 12:30 a.m. The fainter, orange planet Mars, also in Virgo, follows Jupiter into the sky two hours later. Venus, the brightest planet, is roughly in line with Jupiter and Mars and is visible by 3:30 a.m.
The waning crescent moon rises between 1:30 a.m. and 4:59 a.m. through the 9th. It appears close to Jupiter on the 4th, close to Mars on the 5th, and is especially close to Venus on Monday the 7th. In fact, at Los Angeles, the moon will cover–or occult–Venus from 8:05 a.m. until 9:55 a.m., PST. The moon will take 40 seconds to cover and later to uncover Venus. Even though the occultation takes place in a daytime sky, you may be surprised at how easy it is to see Venus even with the unaided eye with the moon to guide your gaze. Binoculars or a telescope are recommended for a detailed view as the moon glides over Venus. The time and duration of the occultation is different for the other parts of North and Central America from where it is visible.
Comet Catalina, C/2013 US10, is glowing at magnitude 6–bright enough to be seen without difficulty through binoculars. Located in the constellation Virgo the Maiden, comet Catalina is well placed for viewing by 5:00 a.m. Visually, the comet appears as a small out-of-focus star, but photographs reveal the comet’s dust and gas tails streaming out at widely separated angles from one another. On the morning of the 4th, the comet is located 7 degrees, a little more than one binocular field-of-view, to the lower left of Venus. By the 7th, comet Catalina is only 4 degrees to the left of Venus, close enough so the comet, Venus, and the moon (three hours from occulting Venus) are all visible in the same binocular or telephoto lens field-of-view! By the 9th, comet Catalina will be 5 degrees to the upper left of Venus in a sky free from moonlight. More detailed viewing information is available at the Sky and Telescope comet Catalina webpage.
The International Space Station makes a passage high over Los Angeles on Saturday evening, December 5. The orbiting laboratory, a home to six astronauts and cosmonauts of different lands, appears above the southwest horizon at 5:38 p.m., reaches its highest point, 64 degrees high in the northwest, at 5:41 p.m., and then vanishes into Earth’s shadow when 17 degrees above the northeast horizon at 5:43 p.m..
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 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, December 19.
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From Griffith Observatory, I’m Anthony Cook and I can be reached at griffithobserver@gmail.com