Shooting the night sky with my D7000. Best Lense?

I will be taking my D7000 out to shoot the stars. I do not know what lenses may be best for this though. I only got lenses that have an aperture f/3.5-5.6. Would I need one with a lower (max.) aperture? 1.4, 2.8?

Any recommendations?

Must be under $800. Nothing professional yet.

Thank You

Wide angle lenses work best for star photography. I would suggest the AF-S 28mm, f/2.8G lens. As a bonus it's under your budget and considered by many as a "professional lens". Also, anything 30 secs and under will give fairly "round" looking stars, anything over 30 sec will begin to give you stars with tails. Experiment with ISO but I've found ISO's between 600-1250 to give me the best results on my D7000.

This was shot with a 14-24mm @ 30 sec, ISO-1250