The Art Of Figuring
This pretty art piece is actually a precise measurement of my progress in telescope mirror grinding. It looked fun enough out of context I decided to post it!
You’re looking at multiple overlaid square images. Each one is a Ronchi test, which tells me the shape of my mirror on a nanometer scale in the shape of the red stripes. As I polish the mirror, it changes shape, so after 20 minutes of polishing I want to measure the new shape. Each time I test, I precisely align my handheld tester, and then take a photo with my phone. Since the tester is in a different place at a time, I have to place my phone on its corner and lean it to one side to put the camera at the right height - but that rotates the image, so afterwards I load up the Ronchi test images in Krita and de-rotate them so the stripes go up and down, so I can compare the images as I grind. You’re looking at a Krita file with many Ronchi images, each rotated and scaled so the mirror is the same size and in the same place. It makes a nice flower shape!