Comet McNaught sports amazing tail

Comet McNaught is displaying a spectacle not seen for centuries during its dazzling sunset show in the southern hemisphere. The celestial visitor's close encounter with the Sun last week released vast quantitites of dust from within its icy head. The debris, trapped for aeons while it lay in the frozen depths of space, have spread into curtains of light, called synchrones, across a great swathe of the night sky. The head of the comet - discovered by Scotsman Robert McNaught, from Prestwick, Ayrshire - is now only visible to spectators in the southern hemisphere. But its 25-million mile long, fan-like tail is so extended that observers have been recording with cameras in northern skies, including the UK. Robin Scagell took the photo shown here on the night of Sunday, January 21, from near Charlbury in Oxfordshire. Despite a bright crescent moon, rays can be seen streaking upwards through Aquarius. On previous moonfree nights, they have been seen more clearly, such as in this image by Pete Lawrence, from Selsey, West Sussex. Astronomers at the European Southern Observatory in Chile described it as appearing like an aurora rather than a comet. Sky and Telescope magazine reports that the phenomenon has not been seen so dramatically since French astronomer Jean-Philippe Loys de Cheseaux sketched a comet's fan-like tail protruding above the horizon in 1744. ©PAUL SUTHERLAND, SpaceStories.com

Bright comet appears in twilight sky

Stargazers have been surprised by a bright new comet that has appeared low in the twilight sky. The cosmic wanderer, discovered by a Scottish astronomer, has flared in brightness as it makes a grazing flypast of the Sun. It is already brighter than virtually all stars. Some experts estimate Comet McNaught could become even brighter than the brilliant planet Venus and produce a spectacular long tail by the end of next week. The comet was first spotted deep in space by Robert McNaught, originally from Prestwick, Ayrshire, on a photograph he took at Australia's Siding Spring Observatory in New South Wales. Its extreme orbit is bringing it to within half the distance from the Sun of its closest planet, Mercury. It will pass just 15.8 million miles from the Sun on January 12, called perihelion, and then rapidly heads southwards becoming visible only in the southern hemisphere as it fades. At the moment, the comet is visible very low down in bright twilight skies before sunrise and after the Sun sets. Photographs show it has already grown a tail. Despite its brightness, the fact that the comet is close to the sun means it is not easy to see. Bright twilight, low cloud and haze plus buildings on the horizon all create difficulties. Robin Scagell, of the UK's Society for Popular Astronomy, said: "If you get clear skies towards the south-west after sunset or towards the south-east before dawn, it is well worth having a look. Bright comets often take us by surprise and can be very unpredictable. It will be fascinating to see how Comet McNaught develops." One observer who found it on New Year's Day evening was David Moore, from Dublin, Ireland. He picked it out in strong twilight with binoculars. A number of photos of the comet appear at SpaceWeather.com. Robert McNaught, who now lives in Australia, has previously discovered 30 other comets. Our chart with this article shows the comet's position in the south-western evening sky on January 9 and January 12 at around 16.45pm local time from the latitude of London. ©PAUL SUTHERLAND, SpaceStories.com

Nasa urges lunar meteor watch

Nasa scientists have opened up a fascinating new field of observing for amateur astronomers - meteor impacts on the Moon. The space agency has found that impacts powerful enough to be seen from Earth happen surprisingly frequently. At least five were recorded as flashes of light on one night last month. Nasa expert Bill Cooke recorded the blasts, ranging in power from 50 to 125 lbs of TNT, as the Earth passed through a cloud of debris left by a Near Earth Asteroid called Phaethon. The asteroid is well known as the source of a major meteor shower called the Geminids every year in mid-December. Meteoroid particles burn up before reaching the ground on Earth. The impacts from the same shower on the moon were spotted on December 14. There is no atmosphere on the moon and so the meteors struck the ground at around 78,000mph. Cooke, of Nasa's Meteoroid Environment Office in Huntsville, Alabama, said: "At that speed, even a pebble can blast a crater several feet wide. The flash of light comes from rocks and soil made so hot by impact that they suddenly glow. We saw about one explosion per hour." Cooke's group watched the moon using two 14-inch telescopes linked to specialist CCD digital cameras. They were surprised when they first snapped a meteor impact on the moon in late 2005 but have recorded another 18 since. Nasa are now urging amateur astronomers to use similar top-of-the-range telescopes and off-the-shelf cameras to help monitor the moon for more impacts. They want to assess the risk to astronauts in a lunar colony. Cooke said: "A worldwide network of amateurs, watching the moon whenever possible, would increase the number of explosions we catch." Personally I think it is a great shame that we were not aware of the phenomenon back in 1998 when the November Leonids put on a tremendous "night of the fireballs". Surely they would have produced some fantastic flashes on the Moon. ©PAUL SUTHERLAND, SpaceStories.com