Here's my mirror in a Ronchi test and a Foucault test. I've managed to reduce the turned down edge to a very small area but it's still there, visible in the ronchi as hooks at the edges and in the Foucault as a slight black zone at the bottom left of the image. I've also managed to dig a huge hole in the center of the mirror trying to fix that edge...
- he/him
i try to make the world more interesting
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in reply to @hillexed's post:
how hard is your pitch? I have read that a harder pitch lap will have less of a tendency to turn the edge. ~Chara