February night sky — click on the image below to see a larger version

Comets are the least predictable of all celestial objects, and it was their apparently random behaviour which earned them their status in the ancient world as unrivalled omens and portents.

Despite that fearsome reputation a great comet — its tail blazing across the sky — is one of nature’s great sights. Comet Lulin, which takes centre stage this month is unlikely to be such a great comet; it does not come as close to the Earth as Hyakutake in 1996 or as close to the Sun as Hale-Bopp did in 1997. Nonetheless, it is almost certain to be visible with the naked eye from a dark site and should be easy to spot with binoculars for the whole of February.

Lulin has until now lived a quiet life in the outer reaches of the solar system. Disturbed by some unknown gravitational interaction with its neighbours, it is now passing through the inner solar system for the first time. This makes it even harder to predict what will happen; all we can do is keep an eye on the comet and hope that it brightens more than the conservative predictions suggest.

Lulin’s track is shown on our chart this month. It begins February among the faint stars of Libra, the least distinguished of the zodiacal constellations and best seen at this time of year in the early hours before dawn.

Finding even a comet as bright as Lulin among these faint stars is a challenge, but as it moves west and brightens throughout the month there are two convenient signposts.

The first is the bright star Spica in the constellation of Virgo. Finding Spica, which rises just after midnight at the start of the month, is easy.

Start with the familiar outline of the Plough, and follow the curve of the handle round across the sky. The first bright star you reach, at the bottom of a Y shape, is Arcturus in the constellation of Boötes. Keep going and you come to Spica, a slightly fainter star, steely blue to Arcturus’ warm orange. Virgo is an enormous constellation, the second largest in the sky, with the main body a rectangle of stars above and to the right of Spica.

On the night of the 16th, the comet will be very close to Spica. Point your binoculars in its direction and you should see a fuzzy ball just above the bright star. If you have trouble, put Spica just out of the field of view to avoid its brightness drowning the comet’s light, but it should be found easily enough. Who knows, there may even be a tail visible.

Comet Lulin moves during February along the bottom of Virgo and into the neighbouring constellation of Leo. To find Leo, return to the Plough and take the two stars which make up the side of the bowl nearest to the handle. Follow these down toward the horizon and you reach Regulus at the base of the sickle which is Leo’s most prominent feature. On the 27th the comet, just past its brightest, will be just over half a degree from the star which forms our second convenient signpost.

By then, Lulin will already have passed by the ringed planet, Saturn, which is lurking among Leo’s hind legs. Saturn lies just above the line which joins Regulus and Spica, and at magnitude 0.2 is the brightest thing in that part of the sky. Of the other naked eye planets, both Jupiter and Mars are almost entirely lost in morning gloom, while Venus and Mercury play their traditional roles as evening and morning star respectively.

Mercury reaches its greatest western elongation, when it is furthest from the Sun in the sky, on the morning of the 13th. Despite this, it remains disappointingly low in the sky at sunrise and will be hard to see. Venus, in contrast, is a brilliant object in the southwest just after sunset.

A telescope, binoculars or even, for those with brilliant eyesight, the naked eye will reveal its phase to be a crescent which wanes over the course of the month. The planet will form a conjunction with another crescent, that of the Moon, on the 27th; look west as the sky darkens at roughly 16:45 to catch them among the stars of Pisces.