Okay guys I need help. Usually i can find the answers to stuff like this on elgooG but not this time. I was out taking some astro photos this weekend and couldn't get anything with a set shutter speed. Settings were 18mm/f3.5 iso 3200-6400, 5-25" I wasn't getting any light (black foreground and a handfull of "stars") so I just kept bumping up my shutter time. I finally got to bulb and guessed around 30sec... overexposed foreground. (But set 25sec had a black foreground) I kept playing with the length on bulb and 10 seconds worked great.. but still a set shutter speed of 10sec didn't work. Why would a set shutter speed be different than bulb? I would like to be able to use my set shutter speed for stacking and timelapse purposes. Any advice is appreciated (on this or on how to improve this photo). Here's what I ended up with for the night Nikon d5100 18mm/f3.5 iso6400 ~12"