There’s a few different ways to shot night stars. Personally, here’s my set up.
– An aperture that is as wide open as you can get. I am currently using Canon 24mm f2.8 but a faster, wider angle lens would be better.
– Complete Manual mode, so you can set the aperture and then set shutter to “bulb” mode so you can control the shutter speed beyond 30secs.
– Use the 500 Rule for Full Frame or 300 Rule for Crop Sensor. So divide your focal length by these numbers to get the maximum exposure time before image becomes blurry.
– When focusing, go all the way to infinity, then dial it back a hair or two.
– Take off all filters, no UV, no polarizing…nothing. Take it all off.
– Use a tripod and shutter remote, also stand away from your set up, as ground shake can also be an issue.
– Last but not least, get a star map app for a phone or something to tell you where the stars you want to shoot are located at the time you’re there.
If you don’t have an equatorial mount, Look into getting image stacking software, such as Deep Sky Stacker, or Sequator to reduce noise and enhance your image.
Bring a flash light and experiment with light painting your foreground during the exposure.
Hope that helps. Have fun.