Re: [ATM] ATM: simplest ever unobstructed scope

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

There are all kinds of odd corrector designs for subdiameter
correctors.  Some handle spherial mirrors while others handle
other shapes up to and including hyperboloids.  I've got a windoz
program on my site that helps develop wide angle (read
photographic) telescopes suitable for photographic uses.  Bob
Lind did the origial software and I just adapted it to windoz
with some cute graphics.  Off axis designs can be obtained by
doing the full on-axis scope and then just doing the part you are
interested in.
Bob May

rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net

----- Original Message -----
From: David Harbour <stainless_steel@suddenlink.net>
To: ATM list <atm@atmlist.net>
Sent: Monday, April 28, 2008 4:00 PM
Subject: [ATM] ATM: simplest ever unobstructed scope


> All:
>
> I haven't read anyone posting about the virtues of the tilted
component
> system that is essentially a Newtonian, with a tilted primary
mirror, and
> two simple menisci just downstream from the diagonal to correct
for the
> induced astig. and coma. I have seen versions of this several
times in Sky
> and Tel, over the decades. Surely someone else has.
>
> I corresponded with Sherman Shultz (with a 75 year old
typewriter, ink on
> paper, many decades ago) about curing the astig. in his 20, or
24" Newt
> (Yoke mounted, ala Hooker 100") at McAlester College; he
favored a tilted
> zero power meniscus, and I favored a little warping harness for
the
> diagonal. What ever happened to Sherman Schultz?
>
> What ever happened to Roger Tuthill, who built that neat
Maksutov Newtonian,
> with tilted components, as an unobstructed Newtonian; why is he
not on our
> list of elite atms? Was he ever? And I have gotten to thinking
about the
> other pioneers from my stacks of now long gone S & T mags- was
Arthur
> Leonard ever on our list? Where is everybody?
>
> Also, If I was going to try an unobstructed instrument with
tilted
> components, I think I would go for one of those designs I saw
that were
> reported to have functioned acceptably- the two or three
designs I saw as
> Newts with a little meniscus, or two, tilted, each, just before
the diagonal
> (out of harm's way of entering light). Does anyone else think
that this idea
> bears investigating?
>
> A long time ago, I asked the great Thomas Cave if I should buy
a largish
> Cassegrain (I talked to him on the phone, when he was still
advertising) he
> said I could make a Newt into a kind of Cass. just by buying a
good Barlow
> lens, and for far less dough. I did just that; many, many years
(decades)
> ago. I understand he has passed....
>
> R-101
>
> P.S. How did the Herschels ever cure the astig. and coma, that
they must
> have had in horrendous amounts, in their big scopes? Does
anyone know? There
> are some interesting "legends" about the Herschels-
>
>
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>

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