Thursday, March 02, 2006

An Early Morning Comet Emerges.

Last night was a group get-together for my department that included the presence of our international crew of Jim and Mark from Cork, Ireland, and Julie from North Ryde, Australia. I had quite a bit to discuss with Julie, as she was the candidate I interviewed, when I was in Australia last year, for the position she currently holds. After catching up on some gossip, she claimed to be less than enthusiastic about our cold temperatures saying: "It's tough to come to a place where the temperature in Fahrenheit (27 degrees) is less than the temperature back home in Celsius (28 degrees, or 82 F)." I couldn't agree more. But we managed to have a fun time nonetheless.

This rare early morning post is to let you know about a new comet that has emerged in the morning skies. Sky and Telescope excerpt:

Sometimes comets give us years of advance warning before they come into good view, and sometimes they take us by surprise. On January 2, 2006, Grzegorz Pojmanski at Warsaw University Astronomical Observatory in Poland noticed a 12th-magnitude comet on a sky-survey image taken the day before in Chile. The comet was in the constellation Indus in the far southern sky. But as soon as astronomers were able to collect more position measurements and calculate an orbit, it became clear that the object would be heading north as it rounded the Sun.

By early February Comet Pojmanski (designated C/2006 A1) was brightening faster than expected for a comet on its trajectory. On February 27th it was glowing at about magnitude 5.5 as it emerged into view very low in the dawn for observers at mid-northern latitudes. It's visible in binoculars — latitude and sky conditions permitting.

The time to look is just after morning twilight begins at your location.
Go out and scan just above the horizon to the left of dazzlingly bright Venus, as shown above. Note the shape of the triangle that Venus and Altair form with the comet's position. (The comet is plotted at 12:00 Universal Time on the indicated dates, which is around dawn on the same date in the time zones of the Americas. As days go by, the entire star field including the comet's position rise slightly to the upper right with respect to the horizon. Venus will remain at about the same height above the horizon but will shift slightly left.)

Each morning, Comet Pojmanski will rise a little higher and become easier to see from northern latitudes, but at the same time it's fading. On March 1st it's only 8° above the horizon at the start of dawn as seen from 40° north latitude, but the comet gains altitude every day: to about 20° on March 8th. By then, however, it will be starting to fade rapidly, probably dimming to magnitude 6.2 by March 11th and losing 0.1 magnitude per day thereafter.

I managed to spot the little bugger this morning without binoculars. It looked like a faint, fuzzy speck in the sky about 15 degrees east of Venus. Through my Tasco 7x50 binoculars, it looked like a bright, hazy star with hints of green. Get out early on one of the next few mornings and see if you can catch a glimpse of this object while it is still fairly easy to spot (weather permitting of course). Good luck!

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