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Old 30-05-2007, 12:56 PM
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CometGuy is offline
Join Date: Feb 2005
Location: Brisbane
Posts: 942
Thanks guys, this is from the comets-ml list:

Discovery of Comet C/2007K5

After a discovering Comet C/2007 E2 on March 15 this year, I am happy to report finding another Comet just 2 months later! Naturally I am elated, especially since this one was a much tougher and challenging find, proving my techniques are working.

This particular comet (designated C/2007K5) was found as a small faint but still rather obvious blue-green haze in my images from the evening of May 26. My initial estimate is mag 13, but I admit I have not attempted more precise photometry and visually the comet could well be brighter. Interestingly the discovery was made during a bright waxing moon and in the evening sky where moderate light pollution prevails. On the evening I had both cameras (a Canon 300D + Canon 350D) mounted the usual way with the 300D pointed towards -18 declination and the 350D pointed towards declination -11. This allows me to image 13 degree wide sweep of sky from west to east. Some 12 individual starfields were covered with both cameras, with 12 subexposures of 90 seconds for each starfield.

The following day, I downloaded the images from my 300D and ran them through the usual automated processing steps (IRIS is used for this). This processing step outputs 2 images per starfield effectively separated by 10 minutes so that moving objects like comets can be identified. By 'blinking' the 2 images one can see objects like asteroids and comets bobbing backwards and forwards. On examining the first image I almost immediately noticed a moving small hazy object with a distinctive blue green colour typical of many comets. I knew I had something for sure, and notified a number of other for confirmation of a possible comet.

Confirmation came on May 28 when both John Drummond and I made followup observations, which were then sent to Dan Green at CBAT. Further followup was obtained on May 29 by Rob McNaught before an official circular (IAUC 8840) announced the new comet as C/2007 K5. Interesting, C/2007 K5 required less than 20 hours of actual searching in contrast to the estimated 1400 hours for C/2007 E2.

The comet itself appears to be quite faint, and will problably remain that way, but a comet none-the-less. Further astrometry is require to calculate an orbit and once this is done the comet will be named.

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