Complete newbie to astrophotography... but with a lot of lenses

Hi all,

I am going to be visiting Africa next month, and will be bringing my NEX-5N along for the ride. I've never done astrophotography, but I know rural Africa has some fantastic clear night sky to shoot in pristine conditions, so I want to bring along a decent kit. I'd like to catch the Milky Way, and perhaps any good large nebulae if possible. No tracking mount or anything fancy (that would just be too heavy!), just a tripod and some lenses. What lenses would you recommend? Fast lenses? Sharp lenses? etc.

I have or will have the following to pick from:

Sigma E 19/2.8

Canon FD 24/2.8

Canon FDn 28/2

Sigma 30/2.8

Konica AR 40/1.8

Sony E 50/1.8

Canon FL 55/1.2

Sony E 18-200 LE

Tokina FD 70-210/4-5.6

I think the Sony 50/1.8 is my sharpest lens wide open, though the Sigmas are famed for sharpness too, as is the Canon 24/2.8. I can't bring everything along but will definitely have the 18-200 for the ride (safari, etc.). It would be a bit slow at tele lengths (f5.6 above 50mm) though. What else should I take? Would you recommend buying a cheap Canon FD tele prime? (I'm thinking a 200, 300 even 400mm f4)