ATM Tinsley 26" problems - second round

[astro <astro@magicnet.net>]

To the group of respondents to my original post - Thank you
To keep the flow of information in an orderly manner I have created a
mailing list  in my address book, so everyone can share in the flow.
Apologies to Mel for the bandwidth, I can take this off list if you
would like me to.

Mel - I also thought that the optics might be pinched and in fact when I
was talking to Bob Pickman (pres. of C.F.A.S. & member of restoration
team) we discussed at length that possibility.  The consensus of
opinions is pinched optics and we will test for and revisit that issue
this week.  Thanks for the link to Pauls site (Spectrum Thin Films),
Paul was instrumental in the restoration project in that he did the
coating on the secondary mirror and did a fantastic job.  In talking to
Bob Pickman, he mentioned that the process that Paul uses requires that
the mirror be suspended upside down in the chamber and he was in doubt
whether or not Pauls facilities could handle the mass of the mirror in
that mode.  The ronchi test was also considered and I am wondering if
the ronchi tester made by Jack Schmidling <sp. (sri - Jack)> could be
used or if a more standard ronchi test must be performed.  Maybe you
could elaborate a little.  I have also linked our web site that shows
the observatory so you can see our dilemma of standing on a ladder
outside.
http://phys.physics.ucf.edu/cfas/Observatory.html

Joe - The optics have not been touched since the restoration and
reassembly, and I will inspect the eyepieces this friday as well as use
my own Naglers in testing to eliminate the possibility of defect.  Bob
Pickman did mention that the optics did not have alignment marks on
them, and so the possibility of rotating the primary mirror in its cell
can be tried.  The only thing is that this is a recent problem with the
double image.  Yes I agree, one has to be there.  I will explore the
possibility of maybe photographing a test and scanning an image and
sending it to this group of respondents.

Bill - thank you for your reply and also for soliciting additional input
from Peter Wlasuk.  We had discussed the collimation idea and on cursory
examination last friday found no obvious defect.  We will go through the
collimation process this week just to eliminate that possibility.  Bob
and I also talked about refiguring and that seems to be a last option as
we were aware that the surface appeared somewhat rough before, but
nothing like the problem we have now.  I have also not heard from anyone
on the list regarding refiguring, but maybe I will now.  Kudos to your
group for the acquisition of the 25.5" mirror.  I am now in the process
of building a 7.5" nominal Wide Field Camera using a 10" f/3 mirror I am
now grinding.  If I had more experience at figuring, I would not
hesitate to undertake the refigure job.  I'm afraid that unlike the
photos showing a very stately  gray bearded Mr. Alvin Clark and the
mammoth 40" objective, you would hear about my loss of hair and
treatment for anxiety.  It is great that we are caretakers of such huge
star canons and one of my best photos (unpublished) is of the core of
M42 showing six core stars and more than six additional stars enveloped
in the inner most tendrils of nebulosity (a 15 sec. exposure at F/16).
You have no idea how much I love driving the scope around the sky (Sky
Pilot?) and teaching others how to setup and use it.  My personal goal
is to bring this older giant upto "Research" grade status with
additional and proper accessories.  I'm sure that we all share the same
thoughts that we must provide every opportunity to enlighten others,
young and old about the beauty of the night sky.

P.S. Our Astrofest is coming up soon after Chiefland's, so maybe we can
arrange tours for visiting amateur astronomers of Robinson Observatory
(crossed fingers).

Warmest regards
Frank Sperl
Robinson Observatory Committee
Central Florida Astronomical Society