[AZ-Observing] UPDATE: Need Help Aligning An Astro-Tech 8" f4 Newt
- From: "Jim Waters" <james.t.waters@xxxxxxx>
- To: <az-observing@xxxxxxxxxxxxx>, <EVAC@xxxxxxxxxxxxxx>, <sac-forum@xxxxxxxxxxxxx>
- Date: Sat, 19 Mar 2011 09:23:56 -0700
Thanks everybody for the replies. There were several problems. First, it
looks like Astro-Tech has some offset in the spider and the spider was 90
degrees off. Second, was more of my problem. Astro-Tech uses a secondary
that can be adjusted in all 3 axis at one time - Secondary tilt, rotation
and up and down positioning of the secondary. The two Dob's I have (18"
Obsession and old Orion 6") use Novak like secondary's and spiders. You can
only adjust 2 axis at one time. I suppose adjusting 3 at one time was too
much for me to handle. When the scope arrived the secondary was positioned
too high with respect to the focuser, tilted to one side quite a bit and
rotated. Third, the alignment screws for the primary were screwed too far
in and the springs couldn't put enough tension on the primary mirror cell to
really adjust it.
The alignment is much better now but not perfect. I will play with it later
today and try to get it exact. I may replace the secondary assembly with a
Protostar unit later. This will improve overall functionality and I don't
like anything plastic in my scopes.
Jim
-----Original Message-----
From: az-observing-bounce@xxxxxxxxxxxxx
[mailto:az-observing-bounce@xxxxxxxxxxxxx] On Behalf Of Jim Waters
Sent: Thursday, March 17, 2011 5:56 PM
To: AZ-Observing@xxxxxxxxxxxxx; EVAC@xxxxxxxxxxxxxx; sac-forum@xxxxxxxxxxxxx
Cc: james.t.waters@xxxxxxx
Subject: [AZ-Observing] Need Help Aligning An Astro-Tech 8" f4 Newt
List;
I received an Astro-Tech 8" F4 (AT8IN) scope earlier this week. It was
badly out of alignment when it arrived and I am having problems getting
everything to line up. I have tried my laser collimator and cheshire
eyepiece with no luck. The images reflect the alignment problem. It's like
I haven't collimated a Newtonian before. I have had an 18" Obsession for
~15 years. I have called Astronomics and they can offer no advice. They
say these scopes are aligned at the factory. With the secondary not even
reflecting light from the primary I disagree.
Can somebody in the greater Phoenix area assist me?
Jim Waters
SAC/EVAC
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