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Re: [ATM] RC Multiple primaries and a single seconday
I think I am missing something.
Why would anyone go to the trouble of grinding, polishing, figuring a large
mirror and then cut it up? Especially if one is then going to put them in a
mount that essentially puts them back together. It seems this just adds an
extreme level of complexity and looses "light" in the process.
I could understand taking several small pieces of glass, making mirrors of
them and then trying to arranging them into a large configuration to collect
and focus light to a single point....I don't know how to do that, however
and I believe a great deal of comma and other distortions would occur.
One could possibly take several mirror blanks, fasten them with plaster(?)
into the final desire configuration/layout and then grind, polish, and
figure them as a group. I guess this could be less expensive as far as the
cost of the blanks versus a single large blank. It still has some
additional complexities and possible distortions.
Jerry Reddell
-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net]On Behalf
Of Arjan te Marvelde
Sent: Saturday, September 16, 2006 5:32 AM
To: atm@atmlist.net
Subject: Re: [ATM] RC Multiple primaries and a single seconday
Bob,
> mountings for each of the 3 sections of the mirror. You also
> lose out on resolution as the 3 airy discs will be larger than
> the 1 of the original diameter mirror. You also lose light
I'm not so sure this is based on correct reasoning. Using wave optics you
cannot just overlay the three large airy disks. When aligned properly the
sum of the disks will produce a smaller one than from each individual
mirror. Refer to the synthesis telescopes for radio astronomy or even the 4
optical ones of the ESO.
But of course you're right in that you will in general have a worse image if
you cut out parts of the mirror.
Another question, what would happen if you used an optical system with an
spherical primary, cut it up and move the parts away from eachother?
Arjan te Marvelde
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