I got a Polarie Vixen star tracker and drove up to the northwest corner of NM, where the sky would be relatively dark. It takes several tries to get the tracker aligned. There's a hole in the body through which you look for the north star, Polaris. The problem is that Polaris is not exactly true north. So you have to keep making small adjustments and taking shots, until you get a satisfactory alignment. Each shot takes a few minutes, so it could take half an hour to get it right. They make a spotting scope attachment that calibrates based on the time of the year exactly where to point. It costs about $300 so I didn't get it. If I were going to do lot of this, I would spend the money.
There's also the problem of droop as the tripod settles into the ground and the camera and lens weigh down the whole thing. And proper focus is essential, which is hard to get at night. Fortunately there were some lights on the horizon that I used with live view focus.
So here's a 90 second exposure using my Nikon D800E with a Sigma 24-36 art lens at 24 mm, f/2.8. ISO was 800, which contributed some noise. I also did shots at ISO 400, 3 minutes, and ISO 200, six minutes. But they weren't quite as sharp, though they were less noisy.
I think that with experience I could get better at this, but I'm not sure how many times I'll be willing to stay out until 4 in the morning.
I think the big glow on the horizon on the left is Albuquerque, over 100 miles away.