December 1998

by Steve Stefanik

The planet Venus returns to the night-time sky as an "evening star" this month making it possible to view all of the planets from sundown to sunup. Look for the brilliant -3.9 magnitude glimmering orb low on the southwestern horizon as the sun sets but it too sets within half an hour or so. It gets higher and remains visible longer with each passing night.

Uranus and Neptune are to the left of Venus but are too far and too dim to be seen with the unaided eye. You’ll need binoculars or at least a small telescope.

The planet Jupiter is still dominant and high in the southern sky as Venus is setting. Although still bright at -2.3 magnitude it no longer is the brightest object in the nightsky with the reappearance of Venus. It still provides hours of enjoyable observing its atmospheric features and four Gallilean moons.

Saturn is about 30 degrees to the left of Jupiter high in the southeast. Although not as bright as Jupiter at magnitude +0.5 its still bright enough to not be mistaken as a star. Its rings are tilted 14 degrees toward earth and many of its moons are visible through a telescope.

Mars makes its way above the eastern horizon about an hour after midnight. Look for the first magnitude ruddy red planet among the stars of the constellation Virgo near the first magnitude bright blue star Spica. It is still too small to make out any of its surface details but it is "growing" in size from 5 arc seconds in early December to 6 arc seconds by the end of the month. It is due south by the time dawn arrives.

Mercury also makes a decent appearance this month. Look for this +0.4 magnitude planet low on the southeastern horizon about an hour and a half before sunrise beginning on the 11th. Don’t confuse it with the first magnitude red-orange star Antares in the constellation Scorpio. It gets as high as 22 degrees from the sun and reaches -0.4 magnitude by the 20th of the month.

The remaining planet Pluto is too small, too far, and too dim to be seen without a telescope of course but it rises just before sunup among the stars of Ophiuchus.

The winter solstice occurs astronomically at 8:56 pm EST on December 21st when the sun appears to "stand still" with respect to its northerly advance on the eastern and western horizons. The good news is that its all downhill from then as the sun begins its advance southward once again.

On the night of the 27th look for the one day past first quarter moon to the left of the planet Saturn. The moon, Saturn, Jupiter, and Venus will be in an arcing single-file line from east to west tracing the ecliptic across the sky.