I have grinded two 8" mirrors. The first one took three years (calendar time) and was a disaster. Lots of scratches on the mirror and astigmatism.
I didn't give up though. Built a second one, applying all tricks that I learnt during the first experience. It turned out very good and only took an year to make.
The linked page doesn't talk about the most painstaking part: the figuring and polishing of the mirror. A good reference is the Stellafane ATM site and books suggested by them.
OT: You are the second poster in this discussion to use 'grinded', instead of 'ground', as the participle of grind. I'm just curious whether that's telescope lingo or just your word choice?
I don't want to call it an error, exactly, because it seems to be part of a trend of verbs being regularised in American English. Lit => lighted etc. I read a novel the other day (Brandon Sanderson's new effort) that repeatedly used 'shined' instead of 'shone' and it was oddly distracting. I wonder how long it will be until all verbs are regular?
I didn't consciously use 'grinded'; my mind just blurted it out based on what I may have read before. Thanks for pointing it out; though I do wish for a more regular English grammar.
Edit: I also just realized I typed "an year". This one was just sloppy.
"Grinded might be considered incorrect in some contexts, but it has grown more common over the past several decades. It’s especially common in American sports commentary and writing, where grind means to overcome adversity by playing hard."
And no, I don't think all verbs will become regular. Ew verbs tend to be, and it is easier for non-native speakers to have regular verbs, but verbs like 'to be' or 'to have' will keep aiming for conciseness (even though we have "me be hungry" as a sort-of counterexample)
The words "grounding" and "grinding" are not related in meaning: "grounding" refers to "ground", meaing the surface of the Earth, and "grinding" is a participle of "grind". See https://en.wiktionary.org/wiki/ground for details.
I didn't give up though. Built a second one, applying all tricks that I learnt during the first experience. It turned out very good and only took an year to make.
The linked page doesn't talk about the most painstaking part: the figuring and polishing of the mirror. A good reference is the Stellafane ATM site and books suggested by them.