Here is another link that might be useful to find it:
http://www.skyandtelescope.com/obser...187930541.html

It is also called Pan-Starr

Dave, rule if thumb that I learned (I'm not an expert):
If you don't want star trails, the longest exposure time is 600 divided by focal length (FF equivalent, for the Rebel multiply the focal length by 1.6). At 15mm that would be 600/(15x1.6) = 600/24_= 25ish seconds

Shoot in manual, wide open, at high ISO. You can try the long exposure noise reduction (in the custom settings). The camera will take a second shot with closed shutter and do some magic math to subtract some of the noise out if the image. Focus manual in Live View at 10x magnification on a bright star in the sky.

The comet will be visible right after sunset, so the sky will be still bright, which means probably lower ISO.

Don't look at the sun through the viewfinder when it is still above the horizon.

Hope that helps,


Arnt