Nikon D3200 long exposure?

Is it possible on the Nikon d3200 to do Lin exposure shots? I have got one and am an amateur astronomer so am wondering whether I can to get the arcs of the stars… Is that what the M, A, S, P on the dial for?

Spoon feeding you will do you no good. READ the instructions, you have a fine camera capable of many things, Explore them in the manual and reap even more benefits than you asked for here!

Nick, the d3200's manual doesn't have a tutorial on how to exposures longer than 30 seconds. Anyways, you're going to need a remote shutter release (just use google, you'll find some) for shots longer than 30 seconds, and a decent tripod. There are quite a few astrophotography tutorials around the web as well, so just look and you will find some.

Yes you can. Couple of things you'll need - a tripod and a remote release.
Shutter speeds up to 30 secs will give you fixed stars. Anything longer than that & you'll begin to get motion blur of the stars - star trails.
To get longer than 30 sec on your camera, switch to M (manual) and dial the shutter speed down until you get 'bulb' showing - this will allow long shutter speeds (as long as the shutter is locked open with the remote).
However, there are 2 ways of doing star trails, one is better than the other;
- first way - take a single long exposure (an hour or so) - the problem with this is that it will drain battery life & more importantly it will cause noise on the sensor from it heating up. You need to do Long Exposure Noise Reduction (LENR) or shoot a dark frame to compensate.
- second way - take lots of 30 sec exposures and stack them together in software. I use http://www.startrails.de/html/software.html
the advantage of this is that there's no sensor heat-up, and you can even change battery between shots if you're quick.
here's one I did in back garden;
If you want to do long exposures of deep space objects that are feint, you need to mount the camera to a telescope (with a T mount & adapter) and use a motorised drive on the telescope mount.