Largest SCT ever built and Date was: ?

What is the largest SCT built to date, where, and date, by whom ?

NK

"Nakomas" schrieb im Newsbeitrag
...
What is the largest SCT built to date, where, and date, by whom ?

NK



Not sure, but the biggest commercially manufactured SCT was AFAIK the
Celestron 22, around 1970.

Juergen

Not sure, but the biggest commercially manufactured SCT was AFAIK the
Celestron 22, around 1970.

Hi:

There may have been a larger professional/custom SCT done at some point (I seem
to recall there was). But if there was, it wasn't much larger than 22 inches.
Tom Johnson pretty much decided that a 22 inch corrector was about the max
that was practically possible. Much above that and the sagging of that thin
glass becomes unmanageable.

Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
Like SCTs and MCTs?
Check-out sct-user, the mailing list for CAT fanciers!
Goto http://members.aol.com/RMOLLISE/index.html

The Armagh Dublin Harvard telescope, for the Boyden station of Harvard
College Observatory, completed in 1949, aperture was 32 inches (84 cm), and
it was described by King p365 as a 'Baker type C4' (citing Baker 1940).
Riekher p334 describes it as a SCT. It was operational in 1950, on the
Fecker mount previously used for the 24" Bruce refractor at Boyden. The
optics are now at Dunsink.

A 37 inch (50 cm) Linfoot design SCT was installed at Mills Observatory,
St. Andrews University, Scotland, in 1953. R.L. Waland fabricated the
instrument.

Both of these telescopes worked well, I believe, and I'm not sure why other
large examples were not built...(as far as I know).

You can get nit-picky about what defines a SCT, but the 'allowable'
variations (in my opinion) have a Schmidt corrector, a convex secondary,
and a concave primary. When you remove a few wavelengths worth of glass,
that changes its behavior but not the class of telescope. And it is
unclear if the big manufacturers use spherical optics anyway.

--
=============================================
Peter Abrahams telscope.at.europa.dot.com
The history of the telescope and the binocular:
http://home.europa.com/~telscope/binotele.htm

(Rod Mollise) wrote in message ...

Not sure, but the biggest commercially manufactured SCT was AFAIK the
Celestron 22, around 1970.

Hi:

There may have been a larger professional/custom SCT done at some point (I seem
to recall there was). But if there was, it wasn't much larger than 22 inches.
Tom Johnson pretty much decided that a 22 inch corrector was about the max
that was practically possible. Much above that and the sagging of that thin
glass becomes unmanageable.

Peace,
Rod Mollise
Author of _Choosing and Using a Schmidt Cassegrain Telescope_
Like SCTs and MCTs?
Check-out sct-user, the mailing list for CAT fanciers!
Goto http://members.aol.com/RMOLLISE/index.html

Does this count as an SCT? (54")...

http://www.ast.cam.ac.uk/history/schmidt/

Regards
Ken

Ken S. Tucker wrote:
(Rod Mollise) wrote in message ...



Does this count as an SCT? (54")...

http://www.ast.cam.ac.uk/history/schmidt/

Regards
Ken

Where's the C?

On Sat, 04 Dec 2004 01:33:57 -0600, Nakomas wrote:

What is the largest SCT built to date, where, and date, by whom ?

Vanderbilt University has a 24" convertible
baker-schmidt/cassegrainian telescope at the Dyer Observatory in
Nashville, TN. The corrector is achromatic. They occasionally have
public nights when you can line up for a glimpse through the eyepiece.
I don't know whether it is the largest ever, but it is the largest
I've ever looked through. It was built about 1950.

Nakomas wrote in message ...
What is the largest SCT built to date, where, and date, by whom ?

NK

University of Virginia has a 40-inch Baker Schmidt, (built in the
'60s?) I'm not sure if it is the largest of its type.

On Sat, 04 Dec 2004 19:42:46 -0600, William Hamblen
wrote:

On Sat, 04 Dec 2004 01:33:57 -0600, Nakomas wrote:

What is the largest SCT built to date, where, and date, by whom ?

Vanderbilt University has a 24" convertible
baker-schmidt/cassegrainian telescope at the Dyer Observatory in
Nashville, TN. The corrector is achromatic. They occasionally have
public nights when you can line up for a glimpse through the eyepiece.
I don't know whether it is the largest ever, but it is the largest
I've ever looked through. It was built about 1950.

Doesn't Palomar have a 48" Schmidt? I think it's a pure Schmidt
camera rather than a Cassegrain.
-Rich

(Rod Mollise) wrote in message ...

Does this count as an SCT? (54")...

HI Ken:

Well...sorta...maybe...no. ;-)

These _are_ Schmidt cameras, afterall.

I agree with answer D -- no. ;-) Schmidt cameras can't be used
visually, have curved focal planes and all kinds of things different
from SCTs. In addition to a different optical configuration, of
course. :-)

I wonder how large the corrector is on
this one (the one with the 54" primary mirror)?

I don't find anything on the page about a 54" but if you're talking
about the 53" Tautenberg Schmidt then 53" is the clear aperture, i.e.,
the size of the corrector. The Oschin 48" Schmidt at Palomar has a
primary mirror 72" in diamter with a corrector plate of 48". IOW,
it's a big-ass corrector (can I say that on s.a.a.?). Very, very
impressive up close.

Mike Simmons