les,
http://www.astrosurf.com/luxorion/re...cessories3.htm
Page down and you'll see the review.
I have the Lumicon version in a tilt cell. Ok for proms but doesn't have the bandwidth for good surface contrast.
Basically designed for use with a 50mm to 80mm ERF mounted on a SCT. Needs a minimum of f20 and above.
(BTW it makes a great blocking filter for a SM40/SM60!!)