Peter
here is the statement that confused me:
The AO-X is a new large aperture AO for the STX and STXL cameras. It requires the FW8G-STXL Filter Wheel or STT-STXL Remote Guide Head and OAG to operate the AO-8X.
This is from
https://www.sbig.com/products/adaptive-optics/ao-x/
Pete