17P/Holmes is a periodic comet with a period of 7.35 years. It was discovered in 1892.
On October 24, 2007, during the most recent appearance of the comet, the comet brightened significantly and unexpectedly. It brightened from magnitude 17 to magnitude 2.8 over a period of a few hours.
Mike Radwick took this photograph of comet Holmes on October 25th, and sent the following message
I’m left almost speechless regarding comet Holmes.
Shown is my attempt to image using a 14.5” Starmaster using a Canon 30D.