

Mirror Grinding - Tomte
http://www.scopemaking.net/mirror/mirror.htm?resubmit=hn

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skypanther
I started, but never finished grinding an 8" mirror. I began making a low-
focal ratio mirror for deep sky observing (which means grinding it to one
curve) then decided I wanted a high-magnification planetary scope instead (and
reground to a different curve) then kids came along and my hobbies stopped.

Along the way, I built my own tools, like the necessary Foucault tester and a
mirror grinding machine. My machine was basically a variable speed drill
driving some eccentric gears that pushed the blank around. I have no idea
whose plans I followed but there are lots out there. I planned to use it for
the polishing stage but ended up giving the machine to a friend who tells me
he used it successfully to polish a mirror.

Mel Bartels is a giant in the amateur telescope making (ATM) community. He's
made many amazing scopes and advanced the art for the amateur a lot. See his
scopes and articles at
[http://www.bbastrodesigns.com/tm.html](http://www.bbastrodesigns.com/tm.html)

Stellafane is an annual gathering of amateur telescope makers (and astronomy
enthusiasts) in Vermont. They have some nicely organized ATM info at
[http://stellafane.org/tm/atm/index.html](http://stellafane.org/tm/atm/index.html)

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jcr
Previous discussion from two years ago has a lot of useful comments and links.

[https://news.ycombinator.com/item?id=6503667](https://news.ycombinator.com/item?id=6503667)

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pstuart
If you're interested in this and live in the SF Bay Area, there's a workshop
for this at the Chabot Space Center that's been ongoing for decades:
[http://www.chabotspace.org/telescope-makers-
workshop.htm](http://www.chabotspace.org/telescope-makers-workshop.htm)

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buserror
Been pondering grinding a mirror for a long while now; however even the blanks
are quite expensive these days (in the UK at least)...

Also, given the amazing amount of time you need to do it, I'd rather go for a
rather impractically large one, otherwise, well, I do have 10" newtonian
'scope already.. But it's unlikely a 16" mirror is a realistic 'first try' :-)

~~~
Starwatcher2001
"Pushing glass" to make a 16" mirror would probably take considerable effort
as well as time. I gather it's quite physical.

I've had some 5 inch blanks for a couple of decades with the intention to have
a bash, just to see if I could get within 1/4 wavelength. I suspect I'll never
have the time, or patience/skill with testing it.

I built a 9 inch Newtonian using bought mirrors and focuser, and plywood etc
for everything else. It would be one step cooler to grind the mirrors too.

~~~
buserror
The grinding could probably be automated somehow; might actually be easier to
get 'random' movements that way too..

I imagine a X/Y/R table with the blank (or tool, alternatively) and the tool
mounted on top on a semi flexible arm that applies pressure mostly on the
center, so it gets to 'rock' a little...

Put a spoon of grit on the blank, place the tool on top, press the timer and
go have a beer :-)

But yeah, that's also a project that'll stick to the back of the queue for
quite a while ;-)

~~~
mangamadaiyan
Someone's already done it:

[http://www.artinso.com/astronomy/mirror-o-
matic.html](http://www.artinso.com/astronomy/mirror-o-matic.html)

This isn't even the original mirror-o-matic, it was just the first link that
google popped up.

