No, it isn't what you think. Or, maybe it is
I'm fairly certain we've all done it. Some of us probably do it more than others. I just did close to an hour of subs on NGC 253, only to look at the subs on the camera and think that I had drift. I then looked over at my scope and noticed the focusing mask in place.
I figured I'd go ahead and process it anyway, as a memento to the occasion.
So I present to you, NGC 253 a la Bahtinov.
10x 5 minute exposures, FLT98
So, who else is guilty and willing to post the evidence?