A new comet, spotted lurking far out in the solar system, may put on a spectacular show in 2013. The celestial visitor is still 700 million miles away, beyond the orbit of Jupiter, but has already been picked up by a robotic telescope.
 

Studies of its orbit show that it will come as close to the sun as innermost planet Mercury in early 2013. By February or March of that year it could become easily visible with the unaided eye and grow a long tail.

Amateur astronomers will hope the comet will be as spectacular as Hale-Bopp was in 1997. That was also bright enough to be picked up well in advance. It went on to dominate the night sky for weeks around Easter.

More recently, Comet McNaught (C/2006 P1) became dazzlingly bright for observers in the southern hemisphere in late January 2007 and put on a decent show for northern observers a little earlier. However, older readers will remember general disappointment among the public caused after expectations were raised for Comet Kohoutek (C/1973 E1) in 1973. N.B. I originally wrote Ikeya-Seki (C/1965 S1) in 1965, about which there was also much hype but which did become brilliant when closest to the Sun.

The new comet is currently extremely faint. It was detected by an automatic telescope called Pan-STARRS 1 in Hawaii – the first part of the Panoramic Survey Telescope and Rapid Response System which will be a powerful eye on the sky designed to stand on the front line of of defence against potentially deadly asteroids.

Early calculations of the new comet’s orbit show that it will come within 30 million miles of the sun in 2013. The Earth lies 98 million miles from the sun and there is no danger of an impact with the Earth.

The comet, which has been labelled C/2011 L4 (PANSTARRS), appears to be heading on a one-way journey among the planets. Experts believe it was dislodged by a passing star long ago from a vast zone of icy debris called the Oort Cloud that is thought to circle the solar system.

Astronomer Richard Wainscoat, of the University of Hawaii, said: “The comet has an orbit that is close to parabolic, meaning that this may be the first time it will ever come close to the sun, and that it may never return.” The university’s discovery report can be read here.

When Pann-STARRS is completed, four separate mirrors, each 1.8 meters in diameter, will have the equivalent light-collecting power to a single 3.5-meter telescope but costing just half as much to build.

Each will be kitted out with a 1.4 billion-pixel camera – a whopping advance on the five million pixels of a chip in a typical quality camera used in the home.

The four, due to be completed next year, will work together to target the same region of the sky at any time, covering a field about three degrees wide, or six times the apparent diameter of the Full Moon.