From: "Tom Krajci" 
To: 
Cc: 
Reply-To: "Tom Krajci" 


From: "Steve B" 

>The first thing that comes to mind, and forgive me if this sounds
>obvious, but what about stray light with a truss design?

>In a typical dome, mine at least, I have 2 CRTs going, and quite a
>few power supply/ equipment LEDs.

See:
http://overton.tamu.edu/aset/krajci/
specifically:
http://overton.tamu.edu/aset/krajci/dobsonian/dobsonian.htm
and look at the photos and text for baffling, and the 'baffle train.'

Granted, I have not used this scope for imaging, but visually I've used it
to observe Saturn when the sun is above the horizon.  That is probably a
stray light environment more hostile than a couple CRT's and LED's in a
dome at night.

Good baffling is possible with a truss tube scope.  (Note:  the
professionals do it...why can't amateurs?)

Good baffling is possible without resorting to a shroud.(Note:  the
professionals also do not use shrouds.)

Shrouds may help with other things, such as keeping warm air out of the
light path, or perhaps some protection against dew, or protection against
curious fingers at public star parties.  Shrouds are large
'sails' in breezy environments.

I hope this helps,
Tom Krajci
Tashkent, Uzbekistan


-+-
Outgoing mail is certified Virus Free. Checked by AVG anti-virus system
(http://www.grisoft.com). Version: 6.0.483 / Virus Database: 279 - Release
Date: 5/19/2003

--- BBBS/NT v4.01 Flag-4