[prova]

just purchased a Nikon D40 and have all the necessary adapters for prime-focus photography as well as a wireless remote for open/close of the shutter.

when you guys post pics of any astrophoto you've taken you say it was taken (for eg. 5 x 3mins exposures), so my question is how to do I set the length of the exposure?

is it a setting within my DSLR? do you sit there with a stopwatch or something else?

wanna try my first shot of M42 tonight, so any help is appreciated !!!!