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From: space@mit-mc
Newsgroups: net.space
Subject: Telescopes
Message-ID: <498@mordor.UUCP>
Date: Sun, 17-Feb-85 18:36:55 EST
Article-I.D.: mordor.498
Posted: Sun Feb 17 18:36:55 1985
Date-Received: Mon, 18-Feb-85 09:44:59 EST
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Organization: S-1 Project, LLNL
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From: Dale.Amon@CMU-RI-FAS

Why hasn't anybody considered building an all electronic telescope?  Why
even bother with a mirror?  A large flat plate of CCD must certainly be
cheaper than the expensive optics and aligning techniques now being used.

I cannot think of a good reason why it wouldn't work, and I'm curious if
anyone out there can see a problem.

For those to whom the idea is not immediately obvious, the main mirror would
be replaced with a flat plate of photomultipliers impinging on CCD.  About
3-4 years ago Scientific American ran an article on some of the new
technology for making the zone plates better and cheaper.

With this approach we can count photons and arrival times immediately.  The
scope would consist of nothing but a tube to prevent extraneous light from
getting in, the 'objective' plate and a computer with humungously high speed
and enormously large storage capabilities.

The only thing I'm not sure of is how to get a good spectral resolution.
What is really desired is a vector of length 4 identifying each impinging
photon over a useful delta-f with <x,y,t,f>

Even with the above computing requirements, it MUST be cheaper than forming
a few tons of glass to within a 1/4 wavelength of a complex 3-d figuring
curve!!!

If anyone decides to build one, please name it after me, or at least send me
the check for the difference between the electronics and the optics...