Eric,
Sorry - I should have posted more info. The ST4000XCM is an OSC (one shot colour) camera, and as such a filter wheel isn't required.
It's a 4.2Megapixel self guided and cooled CCD by SBIG, and has with it the AO8 Adaptive optics module.
The SBIG site has been renovated and a lot of the old products taken down - but info still exists here ...
http://www.optcorp.com/product.aspx?...w=4000xcm&st=2
http://www.optcorp.com/product.aspx?...75&kw=ao8&st=2
PM me if you require any further info.