Photographing the night sky has been another genre of photography that I have not really gotten into. With the nights now getting longer it's getting increasingly accessible. I have previously read a few articles and tutorials on how to take pictures at night and the camera settings are fairly simple.
The limiting factor in taking images of the stars in terms of camera setting is the shutter duration on how long it can stay open before the stars move and blur. The focal length alters the duration, wider the lens the longer the shutter can be open using the "500" rule equation to work it out. The math is you divide 500 by the focal length of the lens.
Using my 18-105 F/3.5 Nikon Kit lens as the example., shooting at 18mm the lens is actually 27mm taking into account the x 1.5 crop factor of my Nikon D7100 and 500 divided by 27mm is around 18 seconds which works as the above image is a 20 second exposure and using a remote trigger to activate the camera or the self timer will also work.