Sky Lights ~ Sagittarius

November 22 - December 21, 2010

Mars too close to the setting Sun and too far from Earth is too dim to see during Sagittarius.

Mercury continues to hug the southwestern twilight horizon. You'll need right timing, clear skies and a flat unobstructed view to spot the elusive planet. Mercury shines at magnitude -0.4, bright enough to see at dusk, however binoculars are helpful in spotting the planet. Best views occur at its greatest elongation, distance from the Sun (21), the nights of 11/30 and 12/1. Late November and early December, about 30 minutes after sunset, look for Mercury low on the southwestern horizon where the Sun has set. Map Bring along binoculars to catch a glimpse of the youngest, slimmest Moon below Mercury 12/6 and a 2-day slim Crescent above the planet 12/7. These are challenging observations. 12/6 4:30pm Map ~ 12/7 Map/Text Mercury sinks out of sight and is in inferior conjunction 12/19. It reappears in the morning sky late December. Mercury is retrograde 12/10-29.

Jupiter is eye-catching and easily seen in the south about 30 minutes after sunset. How early can you spot the planet? Jupiter, moving further from the Earth, is dimming and shrinking in size. However, the gaseous giant, shining at magnitude -2.5, remains the brightest point of light in the night sky until it sets around 1:15am in the beginning of Sagittarius and at midnight by its end. Jupiter is now moving easterly toward its companion planet, Uranus. They will be in exact conjunction 1/4/11. Uranus at magnitude 5.8 can now be seen with binoculars and without an optical aid in a dark sky. Jupiter and the waxing Moon are a visual treat the week of 12/10-16. Jupiter, the First Quarter Moon and Uranus are in close proximity 12/13 at the circlet of Pisces. 12/13 8pm Map Jupiter reaches quadrature 12/16.

Saturn rises in the morning sky at 2:45am in the beginning of Sagittarius and at 1:30am by its end. The planet lies almost half way to the zenith, in the southeastern sky, by the time dawn's early light appears. Brighter Arcturus lies to the north (left) of Saturn, Spica directly below the planet and blazing Venus below Spica and to the left. 12/1 look for the waning Crescent Moon near Saturn. 12/1 5am Map 12/2 the Crescent Moon lies to the right of Venus. 12/2 Map The planet shines at magnitude 0.8, a bit brighter than Spica at magnitude 1.0. As the days unfold, watch Saturn climb higher before dawn. Saturn's telescopic rings are tilting open, revealing more and more of their northern face. The planet's ring tilt is 9 in the beginning of December and 10 by its end. Saturn's Rings 12/15 Generate images of Saturn's ring tilt as seen from Earth with the Solar System Simulator. Our ringed planet is getting brighter as it nears Earth and the rings open to reflect more light. The planet reaches opposition and is at its best 4/3/11.

Venus rises at 4:00am in the beginning of Sagittarius and at 3:30am by its end. Its light pierces the morning twilight, begging you follow it into the daylight sky. Venus blazes at its brightest now, achieving greatest brilliancy 12/4 at magnitude -4.9. 12/2 the Crescent Moon is elegant to the right of Venus. How many celestial bodies can you identify in the vicinity of Venus? 12/2 Map Venus has phases like the Moon. You can see this demonstrated in APOD's animation of the phases of Venus. These phases and more can be seen in this 2010 Evening Animation of Venus. Also check out this montage, which shows Venus approaching inferior conjunction in 2004. During Sagittarius, morning Venus waxes to a 40% illuminated Crescent.

Vega is the brightest star in the northwest setting at 11:00pm in the beginning of Sagittarius and by its end at 9:00pm. It is the western point of the Summer Triangle, which is slowly sinking on the western horizon giving way to the autumn stars overhead. Altair is the triangle's southern point and Deneb the eastern point.

Fomalhaut is the brightest star above the southwest horizon, setting at 11:00pm in the beginning of Sagittarius and at 9:00pm by its end. Fomalhaut is the Southern Royal Star and the brightest star in the constellation Pisces Austrinus below Aquarius. It is part of the celestial sea constellations. In 2010 the brighter, more brilliant Jupiter lies diagonally to the northeast of Fomalhaut. 12/10 7pm Star Chart 

Capella is the bright star in the northeast as the sky darkens. It lies north of the Pleiades. Capella is the brightest star seen the most often. Star Map

The Great Square of Pegasus is a sure sign of autumn. Look for the four stars almost overhead as night begins. Autumn Stars ~ Autumn Dipper? A Flying Horse?.

The Pleiades star cluster is another sign of autumn. Look east as the Sun sets for Taurus the Bull and its bright red Bull's eye, Aldebaran; then look a little west to find the mini dipper-shaped, sparkling Pleiades, the Bull's shoulder. Autumn Stars

Orion The Hunter, the cosmic giant, is a sure sign that winter is near. During the first two weeks of every December you can see him emerge and tower above the eastern horizon around 8:00pm. Around 10:00pm use his belt stars to locate Sirius and Aldebaran and Betelgeuse and Rigel. Navigating with Orion Notice the colors of these 4 stars. Winter Stars

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