Your meter doesn't have to have the same settings as your camera, that is the main thing to understand. So what you do is get a meter that allows the lowest possible f number (e.g. f/1) and the highest possible speed (E.g. 6400) and you make yourself an equivalent exposure chart or spreadsheet. it is quite easy. With your meter set at f/1 and ISO 6400, you should be able to get a decent reading at least somewhere in the scene. Then, once you have that exposure, you have to do a reciprocity correction. I used to have equiv exposure and reciprocity charts in my smartphone for handy reference.
A common approach is to pick the very brightest part of the scene and let that go to the highest zone. So e.g. if you're photographing a moonless sky, you let the stars be the brightest objects in the scene, and there are exposures you can look up that are based on star magnitudes etc. If there is moonlight, then there are charts for that too, which depend on phase and inclination etc. Yeah... most people prefer just to wing it!
In the very worst case, if all else fails, you just shoot whatever exposure you can and develop by inspection (or shoot two and develop one to your best guess, and get it right on #2).
With the latest full-frame dslrs, you can also get very precise readings in near total darkness. With a d700, I shot things that I couldn't actually see. That camera is spooky