Modifications to Stellafane's Telescope Mirror Tester
I like to re use materials whenever I can. Stellafane Observatory's excellent mirror tester had a fantastic knife edge tester viewing window design to follow, but I wanted to use a few things out of the recycle bin.
The holder for the razor blade was made out of plastic food containers, as were the impact panels (for a later post). I covered the holder in electrical tape to reduce any glare. I used the backing of a legal pad for the slider, along with a piece of 1/4" plywood and hex bolts painted black. In making it fully removeable, I can change out or remove the knife edge tester to clear the way for the Ronchi gram. Of course, I can also just slide it out of the way, but I like options. :)