Almost a year ago I had the good fortune of discovering an envelope with the coolest diffraction gratings I had ever seen on my workbench. I don't know where I got them! Everyone that saw them said that they must be designed to rotate, but they are very small, only an inch or so square on plastic substrate.
Then I discovered David Kumpula's "Scan Thru Rotator". I purchased one, and after a lot of work and waiting, I have the device all working, and installed the gratings yesterday. Wow! I am very happy. I stitched together a sample video of all of the gratings to share with y'all - Tim
https://drive.google.com/file/d/1kwk...ew?usp=sharing