Re: ATM Schupmann Design

["Bob May" <bobmay@nethere.com>]

The Stellafane people are selling the Schupmann book.  I have a copy and it
does go through the whole process of how to design a Schupmann with all of
the necessary formulas.  Daly is a member of the Springfield Telescope
Makers as I understand and he had contol of making the 13" Schupmann that is
in the MacGregor Observatory.
I will note that you do need to have well annealed glass in order to make
the instrument perform properly.  The primary is refractive and the tertiary
is a Mangin mirror which means that it really needs to have good refractive
specs.  Using glass of the same melt also completely corrects for any color
error although I'd suspect that close melts on slower optics will work just
fine.  In addition, you don't need to use BK-7 as any glass that you may
have can be used - BK-7 is used because it is fairly cheap.  The spec of the
same melt of glass for all of the refractive pieces is a definite
requirement that is needed.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net