This is the Skywatch Line for Monday, and Tuesday, January 6th and 7th, written by Joe Slomka.
The Sun sets at 4:37 PM; night falls at 6:18. Dawn begins at 5:44 AM and ends with the Sun rising at 7:26.
The brilliant Moon dominates the night sky on both nights. Monday, the 84% illuminated Moon is found in Taurus, below the Pleiades star cluster; it is highest at 8:46 PM and sets at 4:04 AM, Tuesday. Tuesday’s Moon is highest 9:36 PM and situated about 3° above Taurus’ brightest star, Aldebaran; it sets at 5:14 AM, Wednesday.
Early evening features only one bright planet – Venus. The Clouded Planet blazes with minus 4th magnitude in Capricornus. This month, Venus experiences a dramatic increase in altitude. It also sets later from 2 ¾ to 3 ½ hours after sunset and enlarges from 13 to 15 arc-seconds, but shrinks in phase – from 82% to 74% lit. Venus sets at 7:28 PM.
Nightfall finds Neptune and Uranus in their normal positions. Neptune, in Aquarius, still glows with 8th magnitude, about 2 arc-seconds in size and sets at 9:37 PM. Uranus, in Aries, at 5th magnitude, 2 magnitudes brighter than Neptune, appears a bit larger in our instruments and sets 1:40 AM. Finder charts for both can be obtained from astronomy magazines and websites.
Mars is the only morning planet. The Red Planet rises in Libra at 4:12 AM, three hours before sunrise. By 5 AM it can be found about 5° above the star Graffias, one of the brightest stars in the Scorpion’s head.
By nightfall, Orion is already high in the southeastern sky. The bright white star Rigel marks the mighty hunter’s knee. A dim line of stars begins at Rigel and flows westward and downward until it disappears below the horizon. This is the river Eridanus. To see the full extent of this heavenly waterway, one must travel to Florida. There, Eridanus ends with the bright star Achernar, which literally means, “star at the river’s end.” The identity of this stream is a bit of a mystery. Ancient authors differ as to whether it refers to the Euphrates or the Nile. Both rivers were revered from time immemorial. Both were the sources of water and bountiful harvests. It is no coincidence that all the great civilizations and cities were founded along the banks of great rivers. The ancients thought of the Earth as sort of an island surrounded by a great body of water. The creation story in the Book of Genesis alludes to this view, as do Babylonian creation myths. The sky also bears out this vision. For the past several months we have observing water related constellations. Delphinus, the Dolphin, and Capricornus, the Sea Goat, began the procession, followed by Aquarius, Cetus and Pisces. Eridanus spills its heavenly waters to sustain this heavenly aquarium.