Will I be able to use my standard Celestron SCT T-adapter 93633-A to attach my SLR camera to the EdgeHD?

Yes, you can use your standard SCT T-adapter to connect your film or digital SLR to the New EdgeHD optical tube assemblies (OTAs).

However, the EdgeHD has been optimized for astrophotography at a specific spacing between the scope and the camera image plane. 

To take full advantage of the EdgeHD’s photographic performance. Use either the model #93644 (EdgeHD 8” OTA) or model #93646 (9.25, 11” and 14” OTAs) T-adapters. These are designed to position your camera's image plane at the optimal distance.

Each T-adapter is designed for the optimum distance. 

That specific spacing is 133.35mm or 5.25" for the 8" EdgeHD OTA.

 

For the 9.25", 11" and 14" OTAs it is 146mm or 5.75"

 

The same comments apply to other SCT OTA adapters such as radial guiders. They can be used with EdgeHD OTAs but weren't specifically designed for the EdgeHD series optimum distance.