Re: ATM Baffling, open truss telescopes, goto motor drive, and daytime observing

["J&S" <jsstars@worldnet.att.net>]

From: "Tom Krajci" <tkrajci@san.osd.mil>
>Specifically:
http://overton.tamu.edu/aset/krajci/dobsonian/dobsonian.htm
> ... and the bottom portion that talks about the 'baffle train' to
> get an idea of the baffling system used.

Hey Tom!
     Good Job on the baffle under the focuser!
     So many Newtonians are built with no thought given to proper baffling
at this critical point (and not only on Newtonians). A "low profile" focuser
close to the tube has become such dogma in recent years that sight has been
lost of the benefits of a long focus tube (baffling stray light for high
contrast). Though depending on the use for which the telescope is designed,
there are always compromises that must be made - for wide photography, for
instance. (I guess that's why we build so many...)
     It looks like you have done well with the "focuser box" idea.
     An aside: I used to know a guy that built a 9 inch refractor (gorgeous
brass thing weighed 3500 pounds and had a 12 inch Schmidt camera he could
use as a counterweight for the GEM). His daytime job was designing light
baffles for imagers to go into orbit, but he didn't put a single baffle in
that long refractor tube(!). A look at mars through that scope was a
nightmare of glare and ghosts. A 7 inch Questar next to it was supremely
better. After that demonstration, baffles were naturally forthcoming.  :)
(Last I heard he was building a 13.5 inch refractor. Had a 40 inch diameter
RA worm wheel made of naval bronze waiting in the wings for it. That was
about 18 years ago. Wonder if he ever finished it...)

- Jim S.