What looks to be a Takahashi made 90 degree .965" prism diagonal with some sort of lockable rotating dial on the EP side with markings for 360 degrees, like a setting circle. What would be the purpose for this?
I'm assuming this to be Takahashi because of the collet type EP retainment and its identical in design (except for the scale and the size) to the 1.25" Tak prism diagonal that I use with all my refractors. The diagonal is unmarked as to maker or country of origin.
Edited by Tom Duncan, 19 June 2019 - 03:30 PM.