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#1
January 5th 04, 03:19 PM
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commercial manufacture of lenses and mirrors
I tried posting this on sci.astro and got no replies. Maybe this is a better place to ask. Books on amateur telescope making emphasize that machining lenses and mirrors is prone to produce astigmatism, whereas hand grinding lenses and mirrors tends to randomize errors and thereby avoid stigmatism. On the other hand, I haven't heard any complaints about astigmatism in commercially ground lenses and mirrors, and I doubt very much that they are ground by hand. So, what I would like to know is this: what are the machines and processes used by commercial manufacturers of telescopes and what book explains them in detail? Ignorantly, Allan Adler ************************************************** ************************** * * * Disclaimer: I am a guest and *not* a member of the MIT Artificial * * Intelligence Lab. My actions and comments do not reflect * * in any way on MIT. Moreover, I am nowhere near the Boston * * metropolitan area. * * * ************************************************** ************************** 
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#2
January 5th 04, 03:26 PM
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"Allan Adler" wrote in message ... I tried posting this on sci.astro and got no replies. Maybe this is a better place to ask. It isn't. And it wasn't the last time you asked a telescope question, either. Books on amateur telescope making emphasize that machining lenses and mirrors is prone to produce astigmatism, whereas hand grinding lenses and mirrors tends to randomize errors and thereby avoid stigmatism. On the other hand, I haven't heard any complaints about astigmatism in commercially ground lenses and mirrors, and I doubt very much that they are ground by hand. So, what I would like to know is this: what are the machines and processes used by commercial manufacturers of telescopes and what book explains them in detail? Why don't you just contact the commercial manufacturers and ask THEM? Ignorantly, Allan Adler ************************************************** ************************** * * * Disclaimer: I am a guest and *not* a member of the MIT Artificial * * Intelligence Lab. My actions and comments do not reflect * * in any way on MIT. Moreover, I am nowhere near the Boston * * metropolitan area. * * * ************************************************** ************************** If you aren't as you say anywhere near Boston, whyinhell are you posting off a MIT server? Too cheap to get an ISP of your own?
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#3
January 5th 04, 05:24 PM
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I'm beginning to understand why so few people post to this NG. If this is
the greeting you get... Try posting your question to rec.crafts.metalworking, with a "OT" in the header. The place is full of knowlegeable people who are willing to discuss just about any topic. -- Bill Browne www.edgefinderstudios.com "Moonraker" wrote in message news  "Allan Adler" wrote in message ... I tried posting this on sci.astro and got no replies. Maybe this is a better place to ask. It isn't. And it wasn't the last time you asked a telescope question, either. Books on amateur telescope making emphasize that machining lenses and mirrors is prone to produce astigmatism, whereas hand grinding lenses and mirrors tends to randomize errors and thereby avoid stigmatism. On the other hand, I haven't heard any complaints about astigmatism in commercially ground lenses and mirrors, and I doubt very much that they are ground by hand. So, what I would like to know is this: what are the machines and processes used by commercial manufacturers of telescopes and what book explains them in detail? Why don't you just contact the commercial manufacturers and ask THEM? Ignorantly, Allan Adler ************************************************** ************************** * * * Disclaimer: I am a guest and *not* a member of the MIT Artificial * * Intelligence Lab. My actions and comments do not reflect * * in any way on MIT. Moreover, I am nowhere near the Boston * * metropolitan area. * * * ************************************************** ************************** If you aren't as you say anywhere near Boston, whyinhell are you posting off a MIT server? Too cheap to get an ISP of your own?
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#4
January 5th 04, 08:52 PM
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You have a great point there Bill. The last and only time I posted to this
group until now, I got a number of really uncalled-for replies and a few which actually solved my On-Topic question about cutting lubricants for glass. Interestingly the few replies I got of value were direct e-mails. It appears that there a number of knowledgable lurkers hanging around. I certainly don't condone spamminga NG but I didn't find this question all that offensive espcially when this is a lean NG. The one you mentions gets hundreds of posts daily and you are right they do try to help even OT posters (sometimes ad nauseum) Best regards, Charles "Bill Browne" wrote in message ... I'm beginning to understand why so few people post to this NG. If this is the greeting you get... Try posting your question to rec.crafts.metalworking, with a "OT" in the header. The place is full of knowlegeable people who are willing to discuss just about any topic. -- Bill Browne www.edgefinderstudios.com "Moonraker" wrote in message news "Allan Adler" wrote in message ... I tried posting this on sci.astro and got no replies. Maybe this is a better place to ask. It isn't. And it wasn't the last time you asked a telescope question, either. Books on amateur telescope making emphasize that machining lenses and mirrors is prone to produce astigmatism, whereas hand grinding lenses and mirrors tends to randomize errors and thereby avoid stigmatism. On the other hand, I haven't heard any complaints about astigmatism in commercially ground lenses and mirrors, and I doubt very much that they are ground by hand. So, what I would like to know is this: what are the machines and processes used by commercial manufacturers of telescopes and what book explains them in detail? Why don't you just contact the commercial manufacturers and ask THEM? Ignorantly, Allan Adler ************************************************** ************************** * * * Disclaimer: I am a guest and *not* a member of the MIT Artificial * * Intelligence Lab. My actions and comments do not reflect * * in any way on MIT. Moreover, I am nowhere near the Boston * * metropolitan area. * * * ************************************************** ************************** If you aren't as you say anywhere near Boston, whyinhell are you posting off a MIT server? Too cheap to get an ISP of your own?
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#5
January 5th 04, 10:23 PM
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You don't like it? Tough. Use your fillfile.
"Bill Browne" wrote in message ... I'm beginning to understand why so few people post to this NG. If this is the greeting you get... Try posting your question to rec.crafts.metalworking, with a "OT" in the header. The place is full of knowlegeable people who are willing to discuss just about any topic.
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#6
January 5th 04, 10:45 PM
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"Charles A. Peavey" wrote in message ... You have a great point there Bill. The last and only time I posted to this group until now, I got a number of really uncalled-for replies and a few which actually solved my On-Topic question about cutting lubricants for glass. Interestingly the few replies I got of value were direct e-mails. It appears that there a number of knowledgable lurkers hanging around. I certainly don't condone spamminga NG but I didn't find this question all that offensive espcially when this is a lean NG. The one you mentions gets hundreds of posts daily and you are right they do try to help even OT posters (sometimes ad nauseum) Best regards, Charles "Bill Browne" wrote in message ... I'm beginning to understand why so few people post to this NG. If this is the greeting you get... Try posting your question to rec.crafts.metalworking, with a "OT" in the header. The place is full of knowlegeable people who are willing to discuss just about any topic. -- Bill Browne www.edgefinderstudios.com "Moonraker" wrote in message news "Allan Adler" wrote in message ... I tried posting this on sci.astro and got no replies. Maybe this is a better place to ask. It isn't. And it wasn't the last time you asked a telescope question, either. Books on amateur telescope making emphasize that machining lenses and mirrors is prone to produce astigmatism, whereas hand grinding lenses and mirrors tends to randomize errors and thereby avoid stigmatism. On the other hand, I haven't heard any complaints about astigmatism in commercially ground lenses and mirrors, and I doubt very much that they are ground by hand. So, what I would like to know is this: what are the machines and processes used by commercial manufacturers of telescopes and what book explains them in detail? Why don't you just contact the commercial manufacturers and ask THEM? Ignorantly, Allan Adler ************************************************** ************************** * * * Disclaimer: I am a guest and *not* a member of the MIT Artificial * * Intelligence Lab. My actions and comments do not reflect * * in any way on MIT. Moreover, I am nowhere near the Boston * * metropolitan area. * * * ************************************************** ************************** If you aren't as you say anywhere near Boston, whyinhell are you posting off a MIT server? Too cheap to get an ISP of your own? Thought top posting in NGs was for newbies? Geez Charles, you really hold a grudge, I had to go back a ways to find that thread, 11/2003, and your question was answered in the 2nd post after by jk Sinrod, did you want more answers or different answers? The rest was just friendly jabber, total waste of bandwidth, really, but friendly all the same. and sometimes a post just rubs the wrong way, like this one obviously did. Next thing you know, you'll want to know how to make things in glass "perfectly flat" , oops, answered that one already way back in November. While admitting sometimes saying nothing is better than responding to some posts, some days folks (me?) just get up on the wrong side of the bed and feel like letting off a little steam to a post that seems to be asking for it. Too hot here? Oh well.
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#7
January 5th 04, 11:33 PM
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You might want to ask on the ATM mailing list:
http://www.atmsite.org/contrib/Poulson/faq/#13 or better yet, search their archives first: http://www.system.missouri.edu/atm/ -- John
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#8
January 6th 04, 02:58 AM
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Go to the site for the Mirror Lab at the University of Arizona which makes
huge cast glass mirrors and ask them. -- Mike Firth Hot Glass Bits Furnace Working Website http://users.ticnet.com/mikefirth/hotbit46.htm Latest notes http://users.ticnet.com/mikefirth/NTBowl.htm Once again, Empty Bowls will collect for the North Texas food banks - donate. "Allan Adler" wrote in message ... I tried posting this on sci.astro and got no replies. Maybe this is a better place to ask. Books on amateur telescope making emphasize that machining lenses and mirrors is prone to produce astigmatism, whereas hand grinding lenses and mirrors tends to randomize errors and thereby avoid stigmatism. On the other hand, I haven't heard any complaints about astigmatism in commercially ground lenses and mirrors, and I doubt very much that they are ground by hand. So, what I would like to know is this: what are the machines and processes used by commercial manufacturers of telescopes and what book explains them in detail? Ignorantly, Allan Adler ************************************************** ************************** * * * Disclaimer: I am a guest and *not* a member of the MIT Artificial * * Intelligence Lab. My actions and comments do not reflect * * in any way on MIT. Moreover, I am nowhere near the Boston * * metropolitan area. * * * ************************************************** **************************
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#9
January 6th 04, 03:51 PM
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"Top posting"?
-- Bill Browne www.edgefinderstudios.com "Javahut" wrote in message ... "Charles A. Peavey" wrote in message ... You have a great point there Bill. The last and only time I posted to this group until now, I got a number of really uncalled-for replies and a few which actually solved my On-Topic question about cutting lubricants for glass. Interestingly the few replies I got of value were direct e-mails. It appears that there a number of knowledgable lurkers hanging around. I certainly don't condone spamminga NG but I didn't find this question all that offensive espcially when this is a lean NG. The one you mentions gets hundreds of posts daily and you are right they do try to help even OT posters (sometimes ad nauseum) Best regards, Charles "Bill Browne" wrote in message ... I'm beginning to understand why so few people post to this NG. If this is the greeting you get... Try posting your question to rec.crafts.metalworking, with a "OT" in the header. The place is full of knowlegeable people who are willing to discuss just about any topic. -- Bill Browne www.edgefinderstudios.com "Moonraker" wrote in message news
"Allan Adler" wrote in message ... I tried posting this on sci.astro and got no replies. Maybe this is a better place to ask. It isn't. And it wasn't the last time you asked a telescope question, either. Books on amateur telescope making emphasize that machining lenses and mirrors is prone to produce astigmatism, whereas hand grinding lenses and mirrors tends to randomize errors and thereby avoid stigmatism. On the other hand, I haven't heard any complaints about astigmatism in commercially ground lenses and mirrors, and I doubt very much that they are ground by hand. So, what I would like to know is this: what are the machines and processes used by commercial manufacturers of telescopes and what book explains them in detail? Why don't you just contact the commercial manufacturers and ask THEM? Ignorantly, Allan Adler ************************************************** ************************** * * * Disclaimer: I am a guest and *not* a member of the MIT Artificial * * Intelligence Lab. My actions and comments do not reflect * * in any way on MIT. Moreover, I am nowhere near the Boston * * metropolitan area. * * * ************************************************** ************************** If you aren't as you say anywhere near Boston, whyinhell are you posting off a MIT server? Too cheap to get an ISP of your own? Thought top posting in NGs was for newbies? Geez Charles, you really hold a grudge, I had to go back a ways to find that thread, 11/2003, and your question was answered in the 2nd post after by jk Sinrod, did you want more answers or different answers? The rest was just friendly jabber, total waste of bandwidth, really, but friendly all the same. and sometimes a post just rubs the wrong way, like this one obviously did. Next thing you know, you'll want to know how to make things in glass "perfectly flat" , oops, answered that one already way back in November. While admitting sometimes saying nothing is better than responding to some posts, some days folks (me?) just get up on the wrong side of the bed and feel like letting off a little steam to a post that seems to be asking for it. Too hot here? Oh well.
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#10
January 6th 04, 03:59 PM
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The intelligent response I was expecting....
-- Bill Browne www.edgefinderstudios.com "Moonraker" wrote in message .. . You don't like it? Tough. Use your fillfile. "Bill Browne" wrote in message ... I'm beginning to understand why so few people post to this NG. If this is the greeting you get... Try posting your question to rec.crafts.metalworking, with a "OT" in the header. The place is full of knowlegeable people who are willing to discuss just about any topic.
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