This is the Griffith Observatory Sky Report for the week ending Wednesday, January 25, 2012. Here is what’s happening in the skies of Southern California:
Venus, the brightest planet, can’t be missed in the southwest sky in the first three hours after sunset. Although it is the next planet closer to the sun than earth, it is still on the distant side of its orbit, beyond the sun from our viewpoint. As a result, it looks small through a telescope–only 14 arcseconds wide–and gibbous in phase, about ¾ illuminated this week.
Jupiter is the second brightest planet, and can be found high in the south during evening twilight. The giant planet is in Aries the Ram and sets in the west-northwest shortly after midnight. A telescope will show the planet’s disk spanning 40 arcseconds in diameter with dark belts and bright zones of clouds, as well as the four bright Galilean moons–also visible with steadily held binoculars. Jupiter and its family remain featured objects for public viewing through Griffith Observatory’s telescopes.
Pumpkin-hued planet Mars is noticeable above the eastern horizon by 10:00 p.m., about an hour after it rises. Now in the constellation Virgo the Maiden, the planet is best studied with a telescope when it is high in the south at 3:30 a.m. Mars now appears about 11 arcseconds wide. Its most noticeable feature is the brilliant white north polar cap. The dusky regions of Mare Acidalium and Solis Lacus move into prominence during prime observing time from Los Angeles as the week progresses.
Nearly twins in brightness, if not in color–golden planet Saturn on the left and blue-white star Spica of Virgo the Maiden on the right, make an attractive pair of objects separated by 7 degrees. Look for them in the southeast starting at 1 a.m., about an hour after they rise. They cross the meridian, midway between the southern horizon and the zenith just as dawn starts. The rings of Saturn are tilted 15 degrees in our direction.
Comet Garradd, (C/2009 P1) is visible through binoculars and telescopes at magnitude 7 from dark sky locations before dawn. The comet stars the week about 3 degrees east of the midpoint of the eastern side of the “Keystone” of Hercules and is moving about half a degree farther to the north each day. The comet crosses over the northeast corner of the Keystone–only 11 arcminutes from the 4th magnitude star rho Herculis–on the morning of Wednesday the 25th.
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 firstname.lastname@example.org.
– Anthony Cook, Astronomical Observer, Griffith Observatory