On Sat, 7 Jan 2006 19:21:20 -0800 (PST), (Brian Tung)
wrote:

Wouldn't you need good coherence at one-meter scales for that? Isn't
the Fried parameter shorter than that most of the time?

True, as also noted by Don. So you really just need a bright reference-
no problem if you have a nice dye laser pointing back up along the
optical path (and permission from the FAA to use it). Optically, there
are advantages to using a large primary mirror to generate the guide
star, although not everyone is doing it that way.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com