How fast does the moon move through the sky
I'm working on a picture that will include the moon. I'm using an 85mm lens on 35mm film. Problem is the exposure on TMAX 100 will need to be 15-20 seconds. TMY2 would obviously help, but I would really rather use TMX for finer grain. As fine grained as TMY2 is, I would really rather use TMX if I can. So my question is, how short does an exposure have to be to keep the moon sharp? It seems to move pretty damn fast, especially when I'm setting up and it speeds up so I miss the shot :)
I guess ideally I'd make a first exposure for the scene before the moon is in frame, and then just add a short second exposure when the moon is in place. But I can never rely on double exposures with a roll film camera. Too bad I won't be able to use sheet film for this one.