Image of the Month - January 2005

One night, twenty-seven Comets

Hunting comets is popular among amateur astronomers. While some sharpe-eyed individuals scan the skies in search of as yet unknown comets, others keep an eye on the known comets to document their evolution, measure their brightness, the diameter of the coma or the length of the tail. While most of the new comets nowadays are discovered by robotic telescopes scanning the skies searching for hazardous Near Earth Objects and by amateur astronomers taking a close look at the images of the solar satellite SOHO, the numerous discoveries allow observers to select from a number of observable comets every night.

Credit & Copyright: Jerry Armstrong, Winston, Georgia, USA

The montage above shows 27 different comets, all imaged during the night of December 20-21, 2004, by Jerry Armstrong in Winston, Georgia, U.S.A., using a MEADE 14" LX200 GPS Schmidt-Cassegrain telescope and a SBIG ST-1001 CCD camera. Exposures varied from 4 minutes to 30 minutes, and each frame is 5.8' x 5.8', with the exception of C/2004 Q2 (Machholz) which is 19.7'x19.7'. Date and time below each image is specified in Universal Time (UT). "The 3/4 moon was present during most of the images", noted Armstrong, and adds: "To my knowledge, this is the most comets imaged in a single night by an amateur astronomer." Click on the picture above to get a full resolution image (1500 x 1460 pixel, 513 kB).

Bernd Brinkmann, Germany, comments on January 4, 2005: "Jerrys note is not just correct: I managed to image and do astrometry on 30 comets in the night from 20./21.02.2004 with the 50 cm f/5 Newton reflector and an ST-8 from A33 (Volkssternwarte Kirchheim) where I was a guest observer."

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