Nixterdemus
Well-known member
Thanks Simon. I opened up one side & saw the copper strap securing the prism cluster and a couple of screws farther inside that appeared to allow twisting left or right of the prism plate.
Four digits in lead pencil on the outside of the prisms, some numbers etched on the plate & on the back side of the prism cover as well.
Four digits in lead pencil on the outside of the prisms, some numbers etched on the plate & on the back side of the prism cover as well.