Every January 4, Earth plows through a trail of debris deposited by an extinct comet called 2003 EH 1 , and we see a meteor shower. Each grain of dust and small pebble strikes the atmosphere at 94,000 miles an hour (42 km / sec) and incinerates in a bright streak of light called a meteor or shooting star. Because the meteors appear to stream from a point in the sky that was once home to the now obsolete constellation Quadrans Muralis, the shower is named the Quadrantids, or simply the "Quads."
Quadrans Muralis the Mural Quadrant was created in the 1790s from faint stars belonging to three different constellations: Boötes, Draco and Hercules. The mural quadrant was once an important astronomical instrument used to measure the precise elevation of stars above the horizon when they crossed the north-south meridian. Several celestial cartographers included the constellation on their atlases, but it never came into popular use probably because it was so faint. The figure eventually fell into disuse and disappeared entirely in the early 20th century when astronomers standardized constellation boundaries. The Quadrantid meteor shower was first recognized in the 1820s when Quadrans Muralis still held a place in the sky. While the constellation may be dead the name lives on.
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Here's the weird thing about the Quads. The old comet's orbit is steeply inclined to the Earth's orbit (see diagram), so we pass through the densest braids of material very quickly. In most meteor showers you get a day or two of decent activity, but with the Quadrantids the peak lasts only 6 hours! If those 6 hours happen in daylight for your location or any time the radiant isn't up, the shower's a minor thing, but if the peak occurs in a dark sky with the radiant up high, you're in for a special treat with up to 120 meteors per hour visible from a dark sky.
[caption id="attachment_115331" align="alignright" width="400"] A Quadrantid fireball flares near the Hyades star cluster (right). Jimmy Westlake via NASA[/caption]
Guess what? The peak occurs around 2:20 a.m. CST (3:20 a.m. EST, 1:20 a.m. MST and 12:30 a.m. PST) on Saturday, January 4. That's as close to a bullseye as we've come in years and worth freezing your butt off to see. Just kidding. Dress warmly and you'll have no problem. Wear insulated boots, your warmest hat, long underwear, snow pants, a 5-pound coat, a neck warmer and clutch sacks of chemical hand-warmers under your mittens if you have to, but don't miss it.
The radiant is low around 1 a.m. local time, starts climbing by 2 and stands halfway up in the northeastern sky at 4 a.m. If the weather's clear I'll be watching starting around 2:30. I've only seen one dead-on Quad shower in my life, and it was very lively. I'd so love to see it another.
All Quadrantid meteors will point back to the radiant while sporadic or random meteors — there are always a few of these — will not. Get those lawn chairs and warm blankets ready. Wake the kids, too, so you can all watch the show on Saturday. You'll also notice at that early hour that the winter stars have shoved off to the west to make way for all the spring stars that speckle the eastern sky on January mornings. A sign of things to come.
