The 48mm T-adapter is the method of choice if you want to attach your full-frame DSLR or astronomical camera to a Celestron EdgeHD OTA. As DSLR CCD chips continue to grow, Celestron has developed this 48mm T-adapter in order to reduce vignetting and allow greater light transmission to your camera's sensor for producing exceptional astronomy photos.
The Celestron Adaptors T adapter for EdgeHD 9.25"/11"/14" comes with a 42mm T-thread for a 42mm T-ring. This smaller 42mm T-adapter cuts the light cone coming from the back of the EdgeHD tube, resulting in significant vignetting in the corners of full-frame sensors. The 48mm T-adapter has a larger aperture so the light can illuminate the entire sensor unhindered and enhance the capabilities of your full-frame sensor.
There is still 55mm of back focus remaining for the camera when the 48mm T-adapter is used on an EdgeHD OTA .