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Naked-eye comet PANSTARRS heads to Northern skies

Jenny Winder, News Writer
Mar 9, 2013, 8:00 UTC

Sen—Comet 2011 L4 (PANSTARRS) that has been delighting astronomers in the southern hemisphere, is now entering the twilight skies of the northern hemisphere.

PANSTARRS is named after the Panoramic Survey Telescope and Rapid Response System in Hawaii which discovered it in June 2011, as a faint object more than a billion kilometres away. It is thought to be a non-periodic comet from the Oort Cloud, so this could be the first time it has passed through the inner Solar System, and it might not return for another 100,000 years.

Astrophotographer Luis Argerich has been imaging the comet from his base in Buenos Aires, Argentina. He told Sen, "The comet was visible to the naked eye as bright as 4th or 3rd magnitude, but it had a distnctive tail so it appeared to the eye as a small line in the sky. With binoculars the shape of the comet coma and tail were clear and bright, a fantastic view."

Fan-Shaped Tail of comet PANSTARRS. Image credit: Luis Argerich

Fan-Shaped Tail of comet PANSTARRS. Image credit: Luis Argerich

"Imaging the comet is very difficult because it is low in the sky and you have to fight atmospheric extinction, it gives you less than an hour to image it. It needed a clear unobstructed horizon and rural skies or better."

Now PANSTARRS is heading into the Northern Hemisphere. By March 8, it was viewable for those with a totally unobstructed view of the western horizon for about 15 minutes after twilight. On March 10, it will make its closest approach to the sun, about 28 million miles (45 million kilometers) away.

As it continues across the sky, the comet may get lost in the Sun's glare but March 12 and 13 could provide the best viewing opportunity, as it will move further from the Sun and should be easier to spot in the night sky. It could be as bright as the stars in the Big Dipper and it could get even brighter. The comet will then begin to fade away slowly, becoming difficult to view (even with binoculars or small telescopes) by the month's end. The comet will appear as a bright point of light with its diffuse tail pointing nearly straight up from the horizon like an exclamation mark.

This graphic shows the comet

This graphic shows the comet's expected positions in the sky. Image credit: NASA

Nick Howes, Pro Am Programme Manager for the Faulkes Telescope project, and a research associate for the Lowell LARI project on Trans Neptunian Objects (TNOs) told Sen, "What can we expect, we simply don't know, anything could happen, but visibility now is looking very promising for a faintish naked eye object low to the horizon at dusk and good in binoculars, but obviously be careful with them, and wait until the Sun has set."

"The latest observations in the Southern Hemisphere showed a good tail, so we hope this will continue to be visible when it pops up in the Northern Hemisphere" added Howes.

Scientists estimate that a comet bright enough to be seen without the aid of a telescope or binoculars happens only once every five to 10 years. This year we have the chance of two, with comet C/2012 S1 (ISON) due to make an appearance at the end of the year.