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- Xref: sparky sci.astro:12296 sci.space:16237
- Path: sparky!uunet!spool.mu.edu!agate!doc.ic.ac.uk!uknet!mucs!mario
- From: mario@cs.man.ac.uk (Mario Wolczko)
- Newsgroups: sci.astro,sci.space
- Subject: Re: Hubble's mirror
- Message-ID: <1992Nov20.223924@cs.man.ac.uk>
- Date: 20 Nov 92 22:39:24 GMT
- References: <1992Nov3.213906.886@mrdog.msl.com> <1992Nov5.145921.1405@tellab5.tellabs.com> <1992Nov9.125222.1@mdcbbs.com> <83625@ut-emx.uucp> <BxqDzI.B1q@zoo.toronto.edu> <1992Nov17.121839@cs.man.ac.uk> <BxxLo9.I6H@zoo.toronto.edu>
- Sender: news@cs.man.ac.uk
- Followup-To: sci.astro
- Organization: Dept Computer Science, University of Manchester, U.K.
- Lines: 17
-
- In article <BxxLo9.I6H@zoo.toronto.edu>, henry@zoo.toronto.edu (Henry Spencer) writes:
- > I would guess that the null-corrector tests were done with the mirror
- > flat on its back; it would seem the obvious approach. The problem with
- > gravitational distortion -- I would think -- is simply that it requires
- > doing the test in a vertical orientation, which considerably complicates
- > the test facility (if for no other reason, because you need a vertical
- > shaft of considerable height to mount everything in).
-
- I don't know what the spacing between primary and corrector(s) was,
- but I would be surprised if it was substantially less than the
- primary-secondary spacing. So maybe there was a setup in use for the
- corrector tests that didn't need a huge amount of change for a
- primary-secondary test. Of course, this is all easy to say in
- hindsight. The real problem is that the existing tests should have
- caused alarm bells to ring, but the bells were ignored.
- As they say, you can make something foolproof, but not bloody
- foolproof..
-
