The meteor shower that is in progress tonight may not be as easily seen as it was last year, but it’s always worth talking about.
The peak of these Quadrantids is predicted for January 5 at around 2 hours Universal Time, which is 2 AM in Britain but 9 PM on Jan. 4 in eastern North America and 6 PM on the west coast – though Quadrantid meteors in lesser numbers may show themselves in a few preceding and following nights.
The bad news, as so often with meteor showers, is the Moon. Last year, of the three annual showers that in our time can be called the major ones – the Quadrantids of January, the Perseids of August, and the Geminids of December – the Quadrantids coincided with New Moon, the other two with Full Moons. This year it’s just the other way around. The Quadrantids’ radiant is northerly enough to be in the sky just about all night, but with it in the sky just about all night is the glare of the Moon (at its exactly Full position on Jan. 5 at 5 UT.).
An interesting but awkward thing about the Quadrantids is their name – awkward because you have to get into an explanation of it at the outset of discussing the meteors of a year. It would be easier if they didn’t exist and the year started with some Herculids or Pegasids! “Sons of a quadrant.” How can you be the son of a quadrant, and what anyway is a quadrant? (We might try to adapt Edward Lear’s nonsense poem “Who or why or where or what / Is the Akhond of Swat? Does he sit or stand or squat?” but it’s difficult to find rhymes for “quadrant.”) The Leonids are so called, “children of Leo,” because they shoot away from a radiant point in Leo, likewise the Perseids are “children of Perseus,” but there is no Quadrant constellation. But there was one once, in what is now northern Boötes, invented by Lalande in 1795 and later disused. It was one of several newfangled constellations of the Age of Enlightenment that commemorated scientific instruments; a few are still used, mostly in the deep south of the sky – Octans the octant, Microscopium, Reticulum the (optical) net. None of the other disused constellations have their names kept alive in the form of meteor-shower names.
The full name of the constellation was Quadrans Muralis, the wall quadrant. A quadrant was an astronomical instrument for measuring angular height, and a wall quadrant was a large fixed version of it. This illustration shows the ancient astronomer Ptolemy using a quadrant apparently to measure the altitude of the Moon.
Yes, it is worth going out for at least a few minutes as near as you can to the time of the Quadrantids’ peak. There could be as many as three “shooting stars” a minute whose paths trace back to near the Big Dipper, so a few of them may be bright enough to be noticed through the moonlight.