Comet ISON (top) passing above Mars in early October 2013. This was the morning of Oct 8 on a clear morning. This is a stack of 5 x 5 minute exposures at f/4.8 with the TMB 92mm apo refractor and 0.85x Borg flattener/reducer, and Canon 5D MkII at ISO 1600.
The Amazing Sky 