Brightest comet in decades - Comet McNaught

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Stardome Observatory

Brightest comet in decades - Comet McNaught

A new comet is gracing our twilight sky and it already ranked as the second brightest comet recorded since 1935, surpassed only by Comet West in 1975. If it breaks apart, it has the potential to become the brightest seen for several centuries. Some keen observers have even managed to spot it during daylight.

Comet C/2006 P1 (McNaught) was discovered by Australian astronomer Rob McNaught at Siding Springs Observatory on August 7, 2006. At this point it was still 525 million kilometres from the Sun and very faint. That is twice the distance of Mars.

The comet continued to brighten as it approached the Sun but became lost in the Sun's glare during December and was not sighted again until Boxing Day. It brightened sharply leading up January 13th when it passed within 25 million kilometres of the Sun, half the distance of the innermost planet, Mercury.

This placed the comet on the "sun-grazer" category and a prime candidate to be split apart by the Sun's gravitational pull.

The comet's orbit is tilted at 78 degrees to that of the Earth so as it arrived from the north it is now heading south - which is very good news for southern hemisphere astronomers.

Comet McNaught has come from the Oort Cloud, a vast swarm of comets which stretches to nearly a light year from the Sun. It probably has an orbital period measured in millions of years.

Over coming days, the comet will be visible in the southwestern sky straight after sunset above the point where the setting sun crossed the horizon. The best chance to see it will be from a place with a clear western horizon. A useful marker is the bright planet Venus because the comet will be to the left of Venus and at about the same altitude.

Over the next week, the comet will continue to move up the sky and remain visible longer after sunset. The brightness changes of comets are notoriously hard to predict but unless it suddenly starts ejecting more dust and gas, it will steadily fade over the coming week.

Over coming months Stardome will be making high-precision measurements of the comet's position which will be used to refine the orbit.

Important information for Comet spotting
* Find a spot at twilight with a good view of the southwestern horizon as flat as possible the ocean would be ideal.

* Do not use binoculars, as the comet's position close to the sun could mean severe eye damage if you accidentally catch the sun in their binoculars.

ENDS

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