ATM 40" F#3, Shafer-Mak

["Sidor . Kurt" <KSidor@drc.com>]

About a year ago I picked up a surplus finished F# 2.8, 26.5" O.D. sphere.
With the mirror being a beautiful sphere and only 1.6" thick (meniscus) I
don't have the guts to retouch the figure.  I contacted David Schaefer
regarding making a Shaefer-Mak sub aperture corrector for it.  I told him I
was hoping to achieve an F#8 to F#12 final ratio,  he ran some numbers and
my correctors would have been about 9" O.D. and made of thick decent quality
optical glass (expensive).  It didn't look like a very practical approach.
Perhaps if one would settle for an F#15-20 ratio it is more feasable.  I
have not been in touch with David since, he seemed like a very busy man.  I
have since lucked out and found a 23" meniscus of SK16 that I am hoping can
be turned into a Maksutov corrector for my mirror.

Good Luck!

Kurt Sidor
Mechanical Engineer
Dynamics Research Corp.
Encoder Division