By the way, I'm into photography and astronomy, and know quite a bit about optics. Any lens that can go that wide of view will be super expensive or have major optical issues (I won't get technical, but there are many reasons) A mirror is much more straight forward, and avoids these issues. My original idea was to use a 12 inch glass mirror (convex), but now I'm having trouble finding these... seems plastic are more common and larger sizes (18 inch) Here are some websites to get a general idea:
http://www.seeall.com/products/dome_mirrors.html
http://www.reflectionproducts.com/full-dome-mirror.html
It really depends on the quality of image you need. Maybe try glass (cost more) for yourself, then recommend acrylic (cost less) for others to promote this idea. A network of wide angle view cameras watching the sky is a great idea! Also, good quality full sky images would get people interested. I'll try to adapt my idea to a webcam application. Did you know this idea was originally done with old chrome plated hubcaps?


I'm just one of the many: "useless eaters", "cockroaches", "cattle", "sheep"... take your pick.