MDM Observatory's 8K CCD array project:
Telephone: (212) 854-7899
The filter wheel has six positions for up to 5.75in square filters, up to 0.5in thick. Filters are loaded into the position opposite the optical axis via an access hatch through the faceplate facing away from the telescope. Some details are shown in the sketch below.
Assembly Drawing of Components Downstream of Guider, Emphasizing Filter Wheel