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How do you turn a chunk of glass into a telescope mirror?

scopemaking.net

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Re: How do you turn a chunk of glass into a telescope mirror?

#2
Yes but can you make a mirror like Kent did in Real Genius?

"KENT: See! Do you have any idea how hard it is to make a film virtually 100 per cent reflective, one micron thick and apply it to a mirror this shape?"

http://fringe.davesource.com/Fringe/Entertainment/Scripts/Re...

Re: How do you turn a chunk of glass into a telescope mirror?

#3
I grinded some mirror. Nice experience but at end monotonous and boring. Also grinding powder is lethal, I had my appendix removed since I eat some :-(

But I would recommend building ligh dobsonian to everyone. Mirrors are cheap and rest is just wood or aluminium. My 10" has 20 pounds and is flyable.

Re: How do you turn a chunk of glass into a telescope mirror?

#4
post #3

I grinded some mirror. Nice experience but at end monotonous and boring. Also grinding powder is lethal, I had my appendix removed since I eat some :-( But I would recommend building ligh dobsonian to everyone. Mirrors are cheap and rest is just wood or aluminium. My 10" has 20 pounds and is flyable.

One thing the article doesn't mention - how long does it take? How many hours total would be spent grinding?

Re: How do you turn a chunk of glass into a telescope mirror?

#6
post #4
post #3

I grinded some mirror. Nice experience but at end monotonous and boring. Also grinding powder is lethal, I had my appendix removed since I eat some :-( But I would recommend building ligh dobsonian to everyone. Mirrors are cheap and rest is just wood or aluminium. My 10" has 20 pounds and is flyable.

One thing the article doesn't mention - how long does it take? How many hours total would be spent grinding?

It took me 50 hours to do 6" mirror with lambda 1/6, I was 14 and totally left handed.

Re: How do you turn a chunk of glass into a telescope mirror?

#8
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.

Re: How do you turn a chunk of glass into a telescope mirror?

#9
post #3

I grinded some mirror. Nice experience but at end monotonous and boring. Also grinding powder is lethal, I had my appendix removed since I eat some :-( But I would recommend building ligh dobsonian to everyone. Mirrors are cheap and rest is just wood or aluminium. My 10" has 20 pounds and is flyable.

Why did you eat the grinding powder?

Re: How do you turn a chunk of glass into a telescope mirror?

#10
post #3

I grinded some mirror. Nice experience but at end monotonous and boring. Also grinding powder is lethal, I had my appendix removed since I eat some :-( But I would recommend building ligh dobsonian to everyone. Mirrors are cheap and rest is just wood or aluminium. My 10" has 20 pounds and is flyable.

Why did you eat the grinding powder?

It is sticky, very hard to wash and gets everywhere.
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