Xref: utzoo sci.space:4163 sci.crypt:733
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From: lwall@devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: sci.space,sci.crypt
Subject: Re: satellites
Keywords: resolution
Message-ID: <990@devvax.JPL.NASA.GOV>
Date: 12 Jan 88 21:12:02 GMT
References: <873@uop.edu> <2166@umd5.umd.edu> <4910@well.UUCP> <1952@netsys.UUCP> <2209@bloom-beacon.MIT.EDU> <2604@calmasd.GE.COM> <1175@eneevax.UUCP>
Reply-To: lwall@devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 16

In article <1175@eneevax.UUCP> daveb@eneevax.umd.edu.UUCP (David Bengtson) writes:
: For the visible range ( lambda ~ 555 nanometers ) and D = 2 meters,
: theta = 3.39e-7 radians
: For an orbit of 200 miles, features resolve to ~ 5 inches. Not bad, but
: that assumes a perfect atmosphere. 

You guys are all assuming a big round mirror.  Now, it's true that for looking
at faint stars you need a lot of mirror acreage, but there's plenty of light
bouncing off of Lebanon.  You don't need a huge round mirror to get the
aperature you want--just build a frame that will stay rigid in microgravity
and hang several smaller mirrors on it with a common focus.  What's the
resolution for a mirror with an effective aperature of, say 20 meters?  How
many 1 meter mirrors would it take to get the interferometry to come out right?

Larry Wall
lwall@jpl-devvax.jpl.nasa.gov