The December night sky
The cold nights of November made views of the Leonids for more than a few minutes a real challenge. For those who braved the early morning air on November 19, the spectacle was well worth the chill.
In spite of the glaring full Moon, sky watchers across the United States saw hundreds of meteors per hour. The two predicted flurries of comet dust occurred on schedule over Europe about 9:00 p.m. New Mexico time, and again over North America beginning about 3:00 a.m. The flurries corresponded to encounters with two clouds of dusty comet debris. Earth waded into the middle of streams that Tempel-Tuttle had deposited in 1767 and 1866. The North American show was produced by the 1866 dust cloud. Astronomers estimate that 75 percent of the shooting stars that could have been seen were drowned out by the Moon.
Normal activity for this shower gives only a few dozen streaks per hour. According to predictions, the Leonid meteor shower will not be as active as it was this year until at least the year 2098. I am planning on seeing you outside enjoying the show then!
Many theories have been given as an explanation for the Star of Bethlehem. Some suggest it was a comet, others think it was a nearby super nova.
Michael Molnar, an American astronomer formerly with Rutgers University, believes he has found the first reference to the star outside the Bible. He had been studying old Roman coins and noticed that one showed a ram looking back over its shoulder at a star. From this, along with writings in the Mathesis, a book from A.D. 334, Molnar concludes that a rare double eclipse of Jupiter by the moon is the actual event that signaled the Maji. On March 20 and again on April 17, A.D 6, the Moon slid in front of Jupiter. Roman astrologers would have seen this as a sign of the birth of a king.
This is but one of many theories about the events told in the Bible. We may never know for sure just what the Star of Bethlehem really was. But, next time you look up in the sky for the appearance of the Christmas Star, perhaps you should be looking for the disappearance of a planet.
Early morning on December 22 gives a good chance to see Mare Orientale. Normally, we only see the tall mountains on its eastern rim, but for a couple of days much of this multi-ringed impact basin will be in view.
Though the Moon keeps one face toward the Earth, there is a slight wobble back and forth. These wobbles are called librations. In December, you will be able to see the dark lava material on the surface of the Mare as it wobbles into view.
Orientale consists of two concentric rims on the western limb of the Moon. To find it, look just south of the lunar equator along the western edge. It may help to locate the dark crater Grimalde at the equator slightly east of the Moon's edge. Look southwest for Mare Orientale. Use a pair of binoculars to look for the long strips of dark lava making up the two lakes inside.
Next up in the light-show category will be December's meteor shower, the Geminids. This shower should peak around 2:00 a.m. MST on December 14, a Saturday morning. By 2:00 a.m. the Moon will be setting. An average show would produce sixty to a hundred meteors per hour with a few bursts. This year is expected to be a bit dull with only ten to fifteen per hour near the maximum.
The Geminids have the unusual distinction of being derived from Asteroid 3200 Phaethon, which occasionally swings by our neighborhood.
Check the predawn sky on December 1 for a spectacular sight. Venus, Mars, and the crescent Moon will hang in a tight grouping above the eastern horizon.
Venus will be at its brightest on the morning of December 6 before sunrise.
Mars keeps Venus company all month long in the morning sky, both rising a couple of hours ahead of the sun.
Saturn is with us all night. The planet reaches opposition on December 17. Opposition with Saturn occurs when you are able to draw a line from the Sun, through Earth, to Saturn. Since Saturnís orbit is slightly oval, the Earth and Saturn are closer at some oppositions than at others. Because we are closer this time around, Saturn will be at its brightest since 1973.
Jupiter rises late evening, but by the end of the month, it rises about 8:00 p.m. in the east.
- Moon Phases and Winter
- New Moon on December 4
- Full Moon on December 19
- Winter begins on December 21