Telescope making is much alive and there are communities of people (even young people) making their first mirrors right now. Most find their entry in the hobby via the forums (CloudyNights's ATM, Optics & DIY forum, Stargazerslounge, Astrosurf, Astrotreff.de) and amateur mirror maker Discord channels are popping up.
I also recommend anyone wanting to grind their first mirror to read about modern ways of testing in addition to all the classic books (Texereau, Sam Brown, Lecleire) about mirror making.
Bath interferometers changed the game and allow to reach λ/10 wavefront with certainty and repeatability compared to Foucault testing. They are affordable and there's a healthy community around DFTFringe, the de-facto standard interferogram analysis software at interferometry.groups.io
You can also find a Foucault + Ronchi + Bath combo tester's plans on Printables.com and a companion three-axis-table, allowing great testing ergonomics for a low cost if you have access to 3D Printing.
The best resources on how to setup a Bath Inteferometer can be found on the GAP47's website (french, but machine translatable) and GR5's YouTube channel.
My club, the Amateur Telescope Makers of Boston (atmob.org), holds weekly mirror grinding sessions at our clubhouse. Along with another club member I'm working on a diffracting telescope and hope to see first light this spring.
Yes, I'm using a photomask vendor to fabricate the objective. It's in the low hundreds of dollar to get 7um features, a bit more expensive to reach 4um and bloody murder to get 1um (~thousands).
Currently we have some tiny photon sieves, around 1.5mm aperture ~f/14. The next step is going up to 60mm @ f/6.5. The end goal, and I don't know how achievable this is, will be a very large aperture panelized scope. We've discussed making something unsteerably large, sticking it in a field and using the Earth's rotation to sweep the sky.
There's a little bit of trickery to reduce harmonics, though I'm not sure how it'll perform in practice. Please get in touch if you have experience doing diffraction simulation. After first light I plan to write everything up.
There is a very detailed video documentation [0] about telescope building techniques, featuring insights from John Dobson, the inventor of the Dobsonian telescope mentioned on the page.
I made my first 10" telescope - rough and fine ground, polished, figured, and built the telescope and mount at 10 under the instruction famous (later) John Dobson in San Francisco. It's not hype to say he was one of the most significant figures in popularizing astronomy in modern history.
I later went on to make a 16" and then "fell off the wagon" and bought refractors, equatorial mounts and cameras. But I never could have gotten started without him.
I worked at an educational robotics small business in DFW in the late 90s. My boss was super into amateur astronomy and made his own telescopes. Those guys remind me of the amateur rocketry people. Incredibly skilled and knowledgeable group of hobbyists.
I'm always amazed when I see a site that looks like it was built in the early 00s that is still being kept up to date with their Events and News pages.
The convention every year is amazing. It’s so fun to be surrounded by people who are so interested in astronomy that they travel to a convention out of their own state!
The keynote speaker last year was talking about the James Webb Telescope build, absolutely fascinating.
I also recommend anyone wanting to grind their first mirror to read about modern ways of testing in addition to all the classic books (Texereau, Sam Brown, Lecleire) about mirror making.
Bath interferometers changed the game and allow to reach λ/10 wavefront with certainty and repeatability compared to Foucault testing. They are affordable and there's a healthy community around DFTFringe, the de-facto standard interferogram analysis software at interferometry.groups.io
You can also find a Foucault + Ronchi + Bath combo tester's plans on Printables.com and a companion three-axis-table, allowing great testing ergonomics for a low cost if you have access to 3D Printing.
The best resources on how to setup a Bath Inteferometer can be found on the GAP47's website (french, but machine translatable) and GR5's YouTube channel.
Have fun :)
Currently we have some tiny photon sieves, around 1.5mm aperture ~f/14. The next step is going up to 60mm @ f/6.5. The end goal, and I don't know how achievable this is, will be a very large aperture panelized scope. We've discussed making something unsteerably large, sticking it in a field and using the Earth's rotation to sweep the sky.
There's a little bit of trickery to reduce harmonics, though I'm not sure how it'll perform in practice. Please get in touch if you have experience doing diffraction simulation. After first light I plan to write everything up.
Involves chipped paint and household washers.
https://hackaday.com/2020/04/29/test-equipment-shim-washers-...
Simon Winchester also covers it in great detail in his book Exactly: How Precision Engineers Created the Modern World
If you're interested in precision making and how it all came to be it's a very joyful read.
https://svs.gsfc.nasa.gov/5473
Better luck next time to anyone around here and happy eclipse to the people that can enjoy it.
[0] https://www.youtube.com/watch?v=snz7JJlSZvw
https://en.wikipedia.org/wiki/John_Dobson_(amateur_astronome...
I later went on to make a 16" and then "fell off the wagon" and bought refractors, equatorial mounts and cameras. But I never could have gotten started without him.
Btw, for those very interested it looks like they have a yearly convention in VT, with registration opening May 1 — https://stellafane.org/convention/2025/index.html
The keynote speaker last year was talking about the James Webb Telescope build, absolutely fascinating.
I am actually a member of Stellafane.
Impressive stuff though, coming from a former professional astronomer who never built a telescope from scratch.