Celestron - 9.25" EdgeHD (Optical Tube) mount The Azimuth Adjuster Adapter is

The Azimuth Adjuster Adapter is designed for use on the Explore Scientific iEXOS-100 tripod

High-precision worm gears

the penetration of humid room air is prevented

5" gear drive with reinforced ball bearings and gear drive rail for adjustment of the pull-out tube

This gives you then 60mm backfocus

Celestron - 9.25" EdgeHD (Optical Tube) mount The Azimuth Adjuster Adapter isThe EdgeHD optics (Edge High Definition) combine the compact design of a Schmidt Cassegrain with significantly improved imaging at the edge of the image. This optical system not only offers the properties of astrographs, but also produces completely undistorted, sharp images right up to the edge of the large visual and photographic field of view. Not only is the coma outside the optical axis corrected as with other "coma free" optical designs