Hi /r/photography!

I've been mulling over my first extra lens purchase since getting my Nikon D5100 w/ kit 18-55mm. My primary interest at the moment is capturing night/evening shots while I'm visiting observatories. I've gotten quite a few shots I'm fairly happy with. A few examples are here, here, and here.

I'm thinking I'd like my next lens to improve on my ability to capture the starscape shots, specifically. Currently I need to set a rather long exposure time (15 - 30s) at decently high ISO (800 - 6400) to produce the kinds of shots I'd like. I was hoping a wider aperture lens would significantly reduce at the very least the required exposure. Currently, much above 15s the star trails start to become noticeable (something I don't want, at the moment).

I've done some looking around, and it appears my only truly affordable option (<$400, realistically) is the AF-S Nikkor 35mm f/1.8G DX for ~$200.

I'm wondering what everyone thinks about this lens, whether it will give me the results I'm looking for, or if I'll be disappointed. The field of view is smaller than the 18 mm I can get at right now, but I can't seem to find an alternative lens that has such as wide aperture at < 35 mm.

Does anyone have any thoughts, or, just as importantly, alternative suggestions? I'd be willing to wait and save up for a more expensive lens if the difference in quality is going to be sufficiently dramatic.

Cheers,

-Tay