If you try it out, let us know how it goes! I had been wondering how a night sky might come out. I've been shooting for about six months and haven't tried that yet, but having had very limited success with interior shots, I wouldn't be hoping for much. For example, I tried a 3 hour exposure in a big, dark school hall with a christmas tree lit up in the background. Those pinprick tree lights were similar to stars; they were visible, but, of course, they were stationary (and probably brighter than stars would be). Still worth you experimenting though!

It's an interesting idea, but my first feeling is that with the combination of slow paper and a tiny pinhole aperture, you won't see anything if the stars are moving across the sky. A couple of things you could try, though... use fast film (and maybe push process it?) in place of Harman Direct Positive paper, and/or attach the Pinsta to an equatorial tracking mount that follows the stars, giving their light more time to leave an image on the paper. You won't get start trails that way, but you might get a star field.