My best friend was part owner of a ship repair company with 4 other guys, one of them was into telescopes. They would grind their mirror, not sure of the size, at their meetings pushing and pulling back and forth. Took them awhile.
They used a sonotube?, one of those molds for pouring concrete pilings, as the body and built a Dobsonian? telescope that was very large. You had to stand on a stepladder to see into this thing.
I’ll never forget seeing the Orion Nebula through it. It looked just like the pictures in astronomy class I was taking at the time. I was amazed at the quality of the images, especally as it was a DIY project.
Well, you’ve got me motivated now. I’ll have to consider building a telescope with the grandkids.
This time we’ll grind our own mirror! Last time we were in Kenya & the hassles shipping a DIY mirror out to be silvered mandated a ‘store-bought’ mirror.
Sonotubes are a great idea for the larger sizes, perhaps wrapped in a layer of fiberglass cloth & resin to make it water-proof. We used 8” aluminum irrigation pipe, IIRC.
“Dobsonian” -
That is a type of mount for a Newtonian. It was designed by John Dobson, well known amateur astronomer. I met him once at The Orange Blossom Special starparty in Florida. He was interesting, but, a bit of a mooch.
I’ve been using a scope for 45+ years now, and, have never seen any value in grinding my own mirror, when there are so many folks out there that make good ones relatively cheap. It takes all kinds though.
Now building a scope around a mirror is another thing all together. My current scope was hand made by a late member of our club. It’s a fine machine all together, but, the mirrors were bought, not, ground by hand.
All that said, the most important thing is once you get it ready, to go out and use it. Even in the suburbs there are things in the sky to see.