A photograph of Comet Holmes by Geisei's 60cm reflector
Comet Holmes has undergone drastic changes in appearance
and color. I took photographs using the 60cm f/3.5 reflector on the morning
of November 19. The comet fills the photographic frame, which is more than
30' wide. A partially opaque, extremely beautiful blue coma envelopes a
white central condensation. A slightly blurred nucleus and faint background
stars are clearly seen through the coma. The tail remains short. It is
exciting to see how the comet's brightness, appearance, and color are going
to change. "Comet Holmes, are you a ninja in space?"
The following is the observation at Geisei:
Nov. 19.68UT total magnitude 3.3 coma 33' tail 5' 7x50B
With the naked eye the comet at first looked far fainter
compared with a nearby 2nd magnitude star. But with better dark adaptation
the faint coma becomes more easily visible and the comet's overall brightness
increases. This is what is called the total magnitude of the comet. At
a darker observing site the total magnitude tends to be estimated brighter
than from an urban site.
17P/Holmes
5-minute exposure from 23:35, November 17,. 2007
60cm f/3.5 reflector, ISO 400 film