Not something I would usually post...a practice shot and process.
I dont get out enough and shoot at night and last night (saturday was quite clear) so went out and decided just to shoot stars to help get the process right in my head.
Here is a shot taken on my a6000 with a 30mm sigma 2.8 DN lens.
Its 4 shots of 11 seconds iso 3200.
Then processed each shot in LR and the then used PS to stack and manually align and covert to smart object and set the smart object stack mode to median to reduce noise.