Here's my ISON shooting rig.
Using a 2x tele-extender, I have a 1200mm comet canon!
Little blurry (GoPro still), but I will also mount my iPhone to the camera, so I can hopefully get a good line on the distant comet.
I scouted two locations this evening, but both are near me and lots o' city lights. I am going to try and scout some locations a bit away from here for tomorrow night.