Re: [ATM] RE: RC with multiple Primaries

["Bob May" <bobmay@nethere.com>]

The reason why the different length scopes came up is that it is well
understood that you can't make two or more telescopes that are exactly the
same focal length.
Basically you really need to make all of the arriving wavefronts to the
focal plane to be the same wave of light to do the best job of the problem.
First off, not being able to machine several surfaces to that level is your
first problem.  Second is that the mechanical parts of the telescope won't
allow for this close alignment either so basically you're in deep trouble
trying to make a multiple mirror telescope as the ability to put the light
to the focal plane in the best manner.
At the present time, the pros are starting to succeed in getting multiple
telescopes to present the same wavefront to the focal plane at the same time
but that is taking a lot of real esoteric equipment to get there.  Look at
the fun that they are having getting the two Keck scopes matched up.
Bob May
bobmay@nethere.com
http://nav.to/bobmay
http://bobmay.astronomy.net

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