Update October 20, 2014:  The above image is an update with more time added.  Compare it to the image below which was made with only 20 minutes of data shot at ISO 6400 (20×60 sec sub-images.)  I took an additional 30 minutes of 3 minute sub-images at ISO 1600 and added it in, so the combined total is 50 minutes.

Well, the big comet encounter of the year took place tonight, Oct 19, 2014 and Mars and Comet Siding Spring (C/2013 A1) both survived.  LoL.   Seriously, it was a very close encounter if you had darkness when it was closest.  Here in southern Louisiana, it took place during daylight, so I had to catch it after closest approach as C/2013 A1 was bidding Mars farewell.

I had a strange night with some issues, but I managed to get some decent data and also lucked out with some good weather for this event.  This image is from the first set of images I took and it is a composite of comet-only processed and star background processed image stacks.  The comet moved a good distance in the twenty-five minutes it took to get the sub-frames, so I had to isolate it with different alignment and stacking techniques than I use for normal deep-sky images.