September 15, 2009

OBSERVING REPORT OF COMET 217P LINEAR


On the morning of 14th September I spent 40 minutes for comet hunting. The sky was very clear and the Waning Crescent Moon (30%) was present. At 4:50am I decided to observe comet 217P Linear which was shining at magnitude 11 in Eridanus. The comet was close to Beta Eridani star. I had not chart at that moment but I roughly

remembered the location. I was using 8-inch reflector operating at 40X. I set the star-field some 2 degrees 40’ NW from Beta Eridani. I centered a 7th magnitude star forming an elongated triangle with two 9.5 magnitude stars. When I moved the scope to Beta’s direction, a small, round, fuzzy patch of light appeared in the view. It was close to one of 9.5 magnitude stars of the triangle. I thought this should be a comet.

At first I used averted vision and tapped the telescope tube to have glimpses of the comet but then spending few minutes I could see it through direct vision. I kept observing to note its motion until strong light of dawn washed out the view. There was no motion or very less which is hard to note. Later that day I found in the software that the comet moves about 1 degree in 24 hours.

Comet 217P Linear is the faintest comet I have ever observed. After observing this comet I could say my city’s sight for comet hunting is suitable and I can pick up 11th magnitude comets. But one thing I added to my method that from now I have to spent at least 5-8 seconds with using averted vision in each Field of View while sweeping the sky in quest of the cosmic interlopers.