Hello
Last night I set up my new C9.25 to try some Lunar imaging with my LPI and was lucky enough to capture this Lunar halo with a consumer digital camera.
Explanation from Dr Charles Wood of LPOD fame at
http://www.lpod.org/archive/2004/06/LPOD-2004-06-03.htm
"The ring is made of Moon light that is refracted (bent) as it passes through an ice crystal. Moon rings only occur if there are relatively high (and thus cold with ice crystals) wispy clouds. The common hexagonal shaped crystals bend the light by 22 degrees (two fist widths, if you want to measure it), so the entire ring is 44 degrees wide".
Cheers
Dennis