That is the Dorr Universal 43-65mm Camera to Digiscope Adaptor 
The Dorr Universal 43-65mm Camera to Digiscope Adapter is a great innovation from Danubia to take all Digital cameras fitted with a tripod bush. It’s compatible with such a lot Recognizing Scopes Telescopes and Microscopes via manner of the eyepiece clamp which is adjustable from 43-65mm. The Most load is 2kg and springs with a 3 year warranty.
To be used with all compact digital cameras with a tripod bush
Works with such a lot Recognizing scopes, telescopes and microscopes
Adjustable eyepiece clamp