Comet ISON and the 1st Meteor Shower of Winter
UPDATE: Comet ISON was largely swallowed by the sun as it passed our star on Thanksgiving. The debris that emerged at first has dissipated and the comet is no more. R.I.P. ISON.
The first days of December will reveal just how Comet ISON survived its close encounter with the sun. As you look for it in the west after sunset, the first thing you will spot is a light so bright that you think it must be a plane. Yet it’s not. That bright light in the southwest is Venus, shining at its peak brilliancy, magnitude -4.9. On December 5, the moon is just to the upper right of Venus. On December 6, Venus is 26-percent illuminated with a 41 arcsecond disk.
Comet ISON will be to the lower right of Venus in early December. The comet’s motion will be to the northwest, taking it toward the North Star, Polaris, which it will reach in January. As the comet rises higher in the sky it will grow dimmer as it leaves the sun. On December 20 both Venus and Comet ISON are about the same height above the horizon.
The comet may have had its closest approach to the sun on November 28, but its closest pass of Earth will be on December 26 when it gets within some 39 million miles from us.
Jupiter has been rising a bit earlier every evening in Gemini in the east. Watch Jupiter and the moon rise together on December 18. The moon has a couple notable dates before its meeting with Jupiter. On December 14 the moon and the Pleiades star cluster get close, on December 15 the moon enters the head of Taurus the Bull, and on December 17 the skies are lit by the full moon.
Winter is not the most pleasant time to watch a meteor shower, but December offers up two of them anyway. The first is the Geminids, which peak December 13/14. Under excellent conditions up to 80 meteors an hour can be seen. The second shower is the Ursid meteors, which peak over the evening of December 21/22. This is the first official meteor shower of winter, as the solstice occurs earlier that day, December 21, at 9:11 am PST.
(Photo: Stars trail across the sky. Credit: Suszter Balázs SXC)
Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.