Here's a search of the parent forum on the word "microscope". I don't know if the forum software will preserve it across sessions; but you get the idea.
https://www.audioaficionado.org/sear...archid=4106675
I use a Dino-Lite AM4115ZT
Here is a recent picture is of my Benz-Micro LP S at 200X
Formula: ((180-TA0) + TA1) / 2 = SRA