Believers in astral portents of doom can get a double dose of worries tonight not only is there a comet, but the full moon will be eclipsed for four hours, starting at 10.20pm.
A lunar eclipse, caused when the moon moves into the shadow cast in space by the Earth, occurs about three times a year, but tonight's is one of the best for years in terms of visibility in Britain.
"It's very fortunate, in that the circumstances of timing mean the full eclipse will happen at around midnight," said Jacqueline Mitton of the Royal Astronomical Society. "That means the moon will be high in the sky, so the effect will be greater." In the US, for example, the effect will be minimal because the moon will still be low in the sky there.
During the eclipse, which will continue until about 2am on Thursday, the moon may appear to turn copper or orange, or black out altogether. The colouring effect is caused by the sun's rays being bent by the Earth's atmosphere. The effect can be seen with the naked eye.
Meanwhile, the comet Hyakutake - another harbinger of misfortune, according to some - will still be visible in the north-west sky. The comet is fading now and is lower in the sky than it was, but the eclipse will make it easier to see.
The sight of the moon "turning to blood" instilled fear and dread into ancient peoples. In biblical days, a lunar eclipse was believed to have heralded the death of King Herod, while in ancient Japan men would lie on the ground and howl like dogs to ward off its evil effects.
As recently as 1974, 16 people were killed in the Cambodian capital, Phnom Penh, when soldiers fired guns to frighten what they thought was a monkey eating the moon. Lunar eclipses first helped astronomers to work out that the Moon and Earth moved in elliptical, rather than circular, orbits.Reuse content