Sky Talk January 2007: The Quadrantid Meteor Shower

One of the richest yet least-known annual displays of “shooting stars” starts off the new year. But this time around, it will be sharing the sky with a brilliant source of natural “light pollution” – the Full Moon! Despite its interference, this display will still be worth watching.

Among the meteor showers to grace our skies each year, that known as the Quadrantids outranks nearly all of them, including the famed Perseids in August. Its peak hourly meteor rate is only matched by that of the Geminids in December. Under clear, dark sky conditions, observers can expect to see 100 or more shooting stars per hour at its peak (compared to about 80 for the Perseids).

In 2007, the shower will occur on the night of January 3rd into the morning of January 4th, with maximum activity coming before twilight begins, The radiant – that point in the sky from which the meteors appear to stream – lies in the constellation Bootes. And although it doesn’t rise until well after midnight in January, meteors can still be seen shooting from over the northeastern horizon after darkness falls on the 3rd. Meteoric activity increases throughout the night because Bootes continues to rise higher in the sky.

But there’s another more significant factor at play here. During the evening hours, we’re on the side of the Earth “facing away” from the direction the meteors are coming and they have to “catch up” to us. But after midnight we’re turned into the direction of the radiant, casing the meteors to slam into the atmosphere at much higher speeds – resulting in many more of them being seen, and those that are seen to generally be brighter and more spectacular. So losing some sleep to stay up late for a meteor watch is definitely well worth it! But that’s given good sky conditions.

For this year’s display, the Full Moon will rise around sunset and dominate the sky all night. While this will wash out many of the fainter meteors, several dozen per hour of the brighter ones should still be visible — especially after midnight. A helpful technique here is that once the Moon has moved into the western sky (again, after midnight) hide it behind your house or other structure, and with your back to it face east toward the radiant. Since meteor watches typically run many hours, reclining on a lawnchair is usually recommended. But on a frigid January night, you may prefere instead to remain standing and keep moving to stay warm!

Observing meteors is basically a naked-eye activity in order to canvass as large an area of the sky as possible. However, the use of your Edmund binoculars is also encouraged for following the fascinating drifting “smoke” trails left by many of the really bright meteors (which themselves will be moving at medium speed — lasting a couple of seconds — and appear bluish in color). Finally, as to the rather strange-sounding name of the Quadrantid shower, it comes from the long-obsolete constellation Quadrans Muralis. This point in the sky where the radiant lies is now part of Bootes itself.

–James Mullaney
Former assistant editor at Sky & Telescope and author of five books on stargazing.


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