Wednesday,  December 19, 2012 • Vol. 13--No. 154 • 16 of 33 •  Other Editions

2012 Ursid meteor shower active around winter solstice

• The annual Ursid meteor shower always peaks near the time of the December winter solstice, so, in 2012, look for some possible activity over the next few nights. This shower favors the more

northerly latitudes in the northern hemisphere, but even at far northerly latitudes, it's generally a low-key produc

tion.
• Some meteor showers, like the Perseids in August, have been watched each year at the same time for many centuries. But the Ursid meteor shower, which will probably peak on the nights of December 21 or 22, has been observed for only a single century. It was first observed around the turn of the 20th century, when a skywatcher noticed that some meteors seen around this time of year weren't random in their direction of motion across our sky's dome but instead appeared to radiate from near the star Kochab in the bowl of the Little Dipper asterism.
• Kochab and Pherkad guard the North Celestial Pole
• All meteors in annual showers have radiant points on our sky's dome, and the showers take their names from the constellations in which the radiant points lie. The Little Dipper asterism is in the constellation Ursa Minor the Lesser Bear -- hence, the Ursid meteor shower. This shower has been known to produce short bursts of over 100 meteors per hour. But typically the shower is much sparser than that. It might produce only five to 10 meteors per hour at its peak.
• If you want to watch the Ursids, find a country location where you can camp out.

Dress warmly! And plan to spend several hours reclining under a dark sky, sometime during the night. Today's chart, by the way, shows the Big and Little Dippers around 1 a.m. when the Big Dipper is well up in the north-northeast.
• The waxing moon obscures the evening viewing of the December 2012 Ursids. But since the radiant point of the Ursid shower will climb upward after the moon sets

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