Re: [APML] Dobsonian Question

[George Anderson <tillerman1@videotron.ca>]

Hi John

Most solid tube Dobs these days are made with cardboard sonotube. If the
Orion and Celestron ones are made with a steel tube then sagging will be
substantially reduced.
A mount may be good for visual work, but it may not have the precision
required for prime focus photographic work. I am not familiar with the
Orion Atlas mount so I can't comment on what the performance is like.

George Anderson
Montreal Canada

Clear skies and good health

"Herbold, John W." wrote:
> 
> Ok good information, but leads to some follow up questions.  Why would the
> steel sonotube sag?  And what should I look for in the mirror cell?
> 
> I talked to Orion about their 10", and my theory was correct the 10"
> Dobsonian scope is the same as the scope on their Atlas 10 EQ Reflector.
> They also verified that the Dobsonian scope could be mounted on the Atlas
> mount at a later time.  This would allow someone to get the aperture scope
> try it, learn it, like it, then get the mount.  Though I am seeing some nice
> Dobsonian trackers out there for around 500.
> 
> I will want to use this for DSLR photography.
> 
> Also a quick update on Sun Moon and Stars post I made with some blurry
> pictures.  On the second trip out with the scope, I heard something banging
> around in the tube.  A quick check reveled a screw from the primary had
> fallen out!  I put it back in, and the others were also very very loose.  So
> I screwed them down as tight as I could. Just kidding, made the snug, then
> backed off a bit.  The laser collimator should be here today.  Bottom line I
> would not recommend a Bushnell 4.5" scope.
> 
> Thanks,
> 
> John W. Herbold Jr.
> 
> NOTICE:  This e-mail and any files transmitted with it may contain confidential or privileged information that is intended only
> for the use of the individual or entity to whom they are addressed.  This information should be treated with the appropriate
> level of security to preclude the disclosure of sensitive or privileged information.  If you are not the intended recipient, you
> are hereby advised that any disclosure, copying, distribution, or the taking of any action in reliance on the contents of this
> information is prohibited.  If you have received this e-mail in error, please notify the sender, delete this e-mail from your
> machine's memory, and destroy the hardcopy information.  Thank you.
> 
> _______________________________________________
> Astro-Photo mailing list
> Astro-Photo@seds.org
> http://seds.org/mailman/listinfo/astro-photo
_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo