The sky at night

Less than a month after the Geminids, another of the three best meteor showers of the year is underway, due to peak tonight. Astronomers have a perverse way of clinging on to outdated terminology, and this shower retains its old name - the Quadrantids - derived from the former constellation Quadrans Muralis (the "Mural Quadrant" - an obsolete instrument for measuring the positions of stars and planets), which was introduced into star charts in 1795 and abolished when the International Astronomical Union adopted the present 88 constellations in 1930. The radiant of this shower actually lies in Bootes. Though the Quadrantid radiant is circumpolar (ie never sets) for UK observers, it only gains respectable height above the horizon in the early hours of the morning at present. Nevertheless, with such a prolific shower, there is a chance of seeing meteors emanating roughly from a northerly direction at any time tonight and over the next two or three days.

Jacqueline Mitton