Griffith Observatory Sky Report for the week ending Wednesday, February 1, 2012

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This is the Griffith Observatory Sky Report for the week ending Wednesday, February 1, 2012. Here is what’s happening in the skies of Southern California:

The waxing crescent moon emerges into the evening sky and passes close to the brightest planets, Venus and Jupiter. The moon is to the lower right of Venus on the 25th, and to the upper right of Venus on the 26th. It then moves close to Jupiter on the 29th and 30th. The moon reaches first-quarter phase on the latter date, and appears in gibbous phase on the following nights.

Through a telescope, dazzling Venus displays a tiny gibbous phase, and appears only 15 arcseconds wide. The planet sets in the west at 8:30 p.m.

Jupiter, in Aries the Ram, has four bright moons that can be seen through steadily held binoculars. A telescope will reveal cloud belts and other atmospheric features across Jupiter’s 40-arcsecond diameter disk. This week, shadows of two of the moons will be visible as black dots on the disk, events called shadow transits. The first shadow transit is of the satellite Io, and takes place on Friday the 27th, between 8:24 p.m. and 10:33 p.m., P.S.T. The other transit by the shadow of tiny Europa takes place on Saturday the 28th between 7:33 p.m. and 9:56 p.m., P.S.T. Jupiter sets in the west-northwest at midnight.

On clear nights, the brightest nighttime star visible from earth is Sirius of Canis Major, the large Dog. Sirius starts the night low in the southeast, and crosses the meridian in the south at about 10:00 p.m., then sets in the southwest at about 3:20 a.m. When Sirius is near the horizon, our atmosphere causes it to twinkle and shimmer in bright colors. Canis Major is the mythological hunting dog of Orion the Hunter, marked by the distinctive row of three stars–the belt of Orion–located to the upper right of Sirius.

Late at night, when Sirius is at its highest in the south, look for a slightly fainter red “star” low in the east. This is actually the planet Mars, now in Virgo the Maiden. With a telescopic diameter of only 12-arcseconds, it is almost as large as it will appear at its meager close-approach to earth in March. With such a tiny disk, it is best to observe it with a telescope when it crosses the meridian just south of overhead at about 3:00 a.m. This week, in addition to the white north-polar cap, Los Angeles observers will see the dark features Mare Acidalium, Sinus Meridiani, and the easiest to identify, triangular Syrtis Major. If you don’t relish the thought of early morning viewing, remember that Mars will be well placed for viewing in the evening sky starting in late February.

Golden planet Saturn is seven degrees to the east of the equally bright (but blue-hued) star Spica of Virgo the Maiden. The attractive pair can be found low in the southeast at 12:30 a.m., about an hour after they rise. They are highest in the south, midway between the horizon and the zenith, just before dawn starts. The rings of Saturn are tilted 15 degrees in our direction and are stunning in a telescope. Saturn will be ideally placed for early evening viewing starting in April.

Free public viewing of the sun during the day and of the moon, planets and other celestial objects at night, is available in clear weather, Wednesday through Sunday, through Griffith Observatory’s telescopes before 9:45 p.m. Check our website for our schedule. The next public star party of the Los Angeles Astronomical Society and the Sidewalk Astronomers is scheduled for Saturday, January 28.

The Sky Report is updated every Wednesday. It may be read and heard on our website, and is found by following the Sky Information links. From Griffith Observatory, I’m Anthony Cook, and I can be reached at