Comet 2009 Y1 Catalina. June 12, 2011.
Combination of 3, 3 minute images, SBIG STL-1001E CCD.
20" f/6.8 cassegrain at prime focus.
Comet 2009 Y1 Catalina reached 13th magnitude in January, 2011. When the image below was taken, the comet had faded to around 15th magnitude.