RE: [APML] Help! Advice on collimating a C14

["Andrew Clegg" <andy@w4je.com>]

Thanks Richard. The C14 is only about six months old. I will indeed check
for anything loose in the optical path. Your friend's experience sounds a
lot like what I hear from others. I just saw a posting on Astromart for a
C14 and the guy had some images of Ganymede he took with his. My views of
Jupiter aren't even as good as his views of Ganymede!

-----Original Message-----
From: astro-photo-bounces@seds.org
[mailto:astro-photo-bounces@seds.org]On Behalf Of Richard Klappal
Sent: Monday, November 29, 2004 1:01 AM
To: Discussion of Film Astrophotography
Subject: RE: [APML] Help! Advice on collimating a C14


Is your corrector plate snug in the front cell and is your secondary firm
within the corrector.  I've heard of older C8/C11/C14s becoming somewhat
loose with age (drying out/compression of fiber shims?)

My C8 has held its collimation, through all kinds of travel/transport, for
several years and was fairly easy to adjust in the first place.  A friends
C14 rarely needs recollimation except after several hundred miles in the
back of his truck, with good padding/cushioning.

It almost sounds like you have something loose.

Richard

-----Original Message-----
From: astro-photo-bounces@seds.org
[mailto:astro-photo-bounces@seds.org]On Behalf Of Andrew Clegg
Sent: Sunday, 28 November, 2004 23:29
To: Discussion of Film Astrophotography
Subject: [APML] Help! Advice on collimating a C14


Gang,

This may not be the best place to ask this question, since everyone seems to
use RCs or refractors, but I thought I'd ask anyway...

I have a C14 CGE, and I am having one &$%#^ of a time getting the thing
collimated. Deep sky views are spectacular, but lunar and planetary views
are basically horrible (my Orion ED80 gives better views). This is
frustrating because in the reviews of the C14 CGE that I've read, they often
mention that the 'scope provides some of the best lunar and planetary images
the reviewers have ever seen.

As I eventually want to move past piggyback astrophotos to shooting through
the C14 itself, I need to find a way to get good collimation. I've tried
collimating on stars (with the help of a friend), but the process is very
slow, tedious, and frustrating (even with Bob's Knobs), and never ends up
with greatly improved images. And when the 'scope is packed up for the
night, collimation is lost, and the next observing session is once again
spent mostly on collimation, in a vein attempt to improve the images. Arghh.

I've read almost everything I can on the tricks of star collimation, but it
just ain't working for me. So the next option is one of the specialized
laser collimators for SCTs, which shine through the optical path of the SCT
in reverse and project a scattered laser spot onto a distant target. I
wouldn't mind trying that, but I really would like to know if anyone has any
experience collimating SCTs (either with a laser or something else) before I
shell out $200 for the laser collimator. Another choice would be collimating
on an artificial star, but again, it would be good to hear some opinions
before sitting down at the workbench to make one of these.

Has anyone had the same trouble as me getting a large SCT collimated? Should
I send the OTA back to Celestron to make sure there isn't something wrong
with the optics? That would cost me a couple hundred bucks, but it would be
worth it if that would cure my problems.

Help!

Clear skies,
Andy
www.w4je.com

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