26 Nov 10
1 edit
http://xmb.stuffucanuse.com/xmb/viewthread.php?tid=7300
I like how he visualizes the focal point, great video.
The mirror in question is 2 square meters, which works out to about 1.6 meters in diameter, about 5 feet across.
Also it has to be pretty darn close to optically perfect to get that fine a focus.