Path: utzoo!attcan!uunet!aplcen!uakari.primate.wisc.edu!zaphod.mps.ohio-state.edu!rpi!uupsi!pbs!pstinson
From: pstinson@pbs.org
Newsgroups: sci.space.shuttle
Subject: telescope mirrors
Message-ID: <9776.26b81e79@pbs.org>
Date: 2 Aug 90 16:37:13 GMT
Organization: PBS:Public Broadcasting Service, Alexandria, VA
Lines: 11

Although I use three telescopes, a 3" Maksutov, an 8" Schmidt/Cass. and a 6"
Newtonian, I may not fully understand mirror design.  I just use them. 
According to an E-mail, design has no effect on spectral response - only coating
does.  Do other telescope experts out there agree with this?  I was under the
impression Infrared, for example, does not focus at the same point that visible
light does and the thing that effects the focal point the most is the curvature
of the mirror.  I don't see how coating alone is going to solve this problem of
more than one focal point.  If the mirror is going to be used primarily for
infrared work, wouldn't its shape be a bit different?  I do know widefield and
planetary scopes, dedicated to those purposes vary significantly in the
degree of curvature.