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Mirror grinding book recommendations Please

Chris

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Chris

Chris

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Hi folks :)

Its been ten years since I first read up on grinding mirrors then the idea got placed on the bucket list and shelved. I have been thinking about the idea quite a bit again over the last couple of years, and now my observatory is pretty much complete I think I'm ready to give mirror grinding a go :) I must say reading some of the Dob build threads on SGL have also inspired me, you guys know who you are :)

Could anybody recommend a book on mirror grinding and figuring that is easy to buy in the UK and easy to follow. I'm after a default recommended text just like Making Every Photon Count is the recommended text for AP.

Also if there are any useful web resources people know about that would be great. I know about Stellafane which is great and this helped me put together an OTA having bought a pre made mirror set.

Any help and advise very much appreciated :)

P.s. I take it Galvoptics is the best place to get my mirror grinding kit from?

Chris

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Chris

Chris

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N.E Howard's 'Handbook for Telescope Making' is also a good book if not a bit old now but Texereaux's is regarded as the one these days.

Stellafane is excellent too, especially for videos which shows you more than a book can.

This is in my bookmarks for some reason so I'll share it. :)

http://www.scopemaki...rror/mirror.htm

Great stuff, I'll Google that book also and thanks for the link, I love the title!

"How do you turn a chunk of glass into a telescope mirror, with a surface accurate to a couple millionths of a millimeter ?

And why do you wish to do so? :grin:

I'm gong to read it now.

Thanks :)

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Chris

Chris

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Stellafane is an excellent site. Always worth a look through if you're planning your own newt.

James

Hi James, I totally agree its an amazing resource, it does seem to be more about Dob builds than the actual grinding process unless I was missing something last time I was on there? I'll re check and see if there are any step by step DIY mirror grinding links on there.

Cheers

Chris

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Chris

Chris

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chirs just buy the blank start grinding and read when you need to :D way more fun !!! oh and make it a 20" :D

ah ah! I like it Dan :D In my head, with how difficult I think the process is, its like saying you want to fly an helicopter!? just get in and press some switches and pull on some levers! :D I know I won't literally go down in flames if I buy a blank and just start grinding, but I might make a mistake which would take longer than if I research the process before hand? Still, the Dan-maverick approach is tempting! :D

Thats another thing? where did you get your grinding blank and tool, pitch, grits etc Dan? See I do remember something from the book I read a decade ago :) I saw that Galvoptics do mirror grinding kits which looked well priced.

http://www.galvoptic.../telescope1.htm

I have a 200p f/6 Dob which although haven't had that long I already absolutely love it! Therefore I wouldn't mind going for more aperture. I know that they recommend a small slow mirror for a first grind, but I know you've bucked this trend so I was thinking 10 or 12" and around f/6, I need to research balance and height before definately aiming for a certain F/ratio. I might follow in your footsteps in terms of just going for a big grind Dan :D

If I was slightly more sane I would perhaps go for a 6" f/9 which would require barely any figuring from what I can gather. Maybe someone can talk me into this sane option? :D

Chris

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Chris

Chris

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No intention of grinding a mirror myself but have bookmarked that free to read link , fascinating stuff , seems so simple really that I may be tempted one day ... :laugh:

Hey Steve, I thought it amazing that the whole book was there to read for free, not sure about it being simple though! :D

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Steve Ward

Steve Ward

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Hi Chris ,

Everything looks simple in a book ... :grin:

After all it's just rubbing one thing on top of another thing until it's the right shape and shiny ..... they've been doing it the same way for 400 years ... !

Quite fancy a go at hand polishihg a 200mm Solar etalon , only needs to be 1/100 wave or so , that'd save me about £35,000 give or take a few grand I guess .... don't worry Ken H , I'm still saving ... :p

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Chris

Chris

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ah yes Steve, everythings relative isn't it :) Compared to that I think a Newt mirror grind would be a piece of cake! :D That reminds me of something else I like about the idea of grinding your own mirror, it would be interesting to get a report at the end to see how good/bad the Strehl and wave is :)

Chris

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Daniel-K

Daniel-K

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i think galvo is your best bet, barry got ours from st helens x2 blanks £50, goto machine mart to get you 80 grit the rest i got from william bell in the states, i tried ringing galvo but they never got back to me, you should do a nice 12" f6

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Daniel-K

Daniel-K

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i doubt out 16" is going to kill our appature fever so our mirror box will take a 18" easy and a 20" at a push with about 1" around the edge, but if we go to a 20" we would have to redo the upper truss and poles but at least we have the box covered :D

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Chris

Chris

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Would be a right downer to spend all that time and then get a rough report though ... :eek:

I guess that you can test them before coating so as to be able to correct/refine ... ?

Yeah it would be pretty gutting to get a test back for a 1/2 wave and a Streh of .5 mirror! Not that I'm sure of the numbers for a bad mirror? I now that 1/10 wave and Strehl of .98 is good! Your probably right about testing before silvering :)

Chris

,

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Chris

Chris

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i think galvo is your best bet, barry got ours from st helens x2 blanks £50, goto machine mart to get you 80 grit the rest i got from william bell in the states, i tried ringing galvo but they never got back to me, you should do a nice 12" f6

I will check Galvoptics more thoroughly as for kits they seem to stop at 10" for about 110 delivered but this inlcudes the secondary and grits and tool, sounds good to me but a 12" would be more of a jump from my current 8", damn aperture fever :D

I have a feeling that they might skimp with grits with the kits so I might be using your links, thanks :)

Chris

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Chris

Chris

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i doubt out 16" is going to kill our appature fever so our mirror box will take a 18" easy and a 20" at a push with about 1" around the edge, but if we go to a 20" we would have to redo the upper truss and poles but at least we have the box covered :D

Good forward thinking there Dan! :)

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P_Monty

P_Monty

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Yeah it would be pretty gutting to get a test back for a 1/2 wave and a Streh of .5 mirror! Not that I'm sure of the numbers for a bad mirror? I now that 1/10 wave and Strehl of .98 is good! Your probably right about testing before silvering :)

Chris

,

Sounds interesting - good luck.

After all its not like the professionals ever got a mirror wrong. Fortunately they spotted the mistake before they blasted into space ... :tongue:

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kirkster501

kirkster501

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N.E Howard's 'Handbook for Telescope Making' is also a good book if not a bit old now but Texereaux's is regarded as the one these days.

Stellafane is excellent too, especially for videos which shows you more than a book can.

This is in my bookmarks for some reason so I'll share it. :)

http://www.scopemaki...rror/mirror.htm

I remember reading that book excitedly when in my early teens, 35 years ago!

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