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Science Forum Index » Astro - Amateur Forum » C14 issue
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Message |
| Antonio Zanardo |
 Posted: Mon Apr 21, 2008 8:33 am |
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Guest
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Hi all,
I recently bought a used C14.
The central screw retaining the secondary cell of the scope became loose,
thus the cell was turning around and moving from side to side as the
corrector plate hole is a bit larger than the cell..
I tightened the central screw without checking the cell centering, then I
collimated and performed the star test.
The inside and outside diffraction patterns are not very good, therefore I
am arguing if the loose secondary cell is responsible for that
unsatisfactory
performance.
Any suggestion on how to check again and correct those issues will be
greatly appreciated.
Antonio Zanardo |
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| Beta Persei |
| Posted: Mon Apr 21, 2008 1:51 pm |
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Antonio,
you may ask the question on
http://home.online.no/~gibala/astro/cct/index.htm also, maybe some guy there
may be of help. I will ask also to my astroclub friends, we have a C14 too.
Clear skies,
--------
Beta Persei
45° 35' N
08° 51' E
remove "_nospam" to reply
"Antonio Zanardo" <antoniozanardoTOGLIMAIUSCOLE@ATlibero.it> ha scritto nel
messaggio news:yI0Pj.62844$FR.267987@twister1.libero.it...
Quote: Hi all,
I recently bought a used C14.
The central screw retaining the secondary cell of the scope became loose,
thus the cell was turning around and moving from side to side as the
corrector plate hole is a bit larger than the cell..
I tightened the central screw without checking the cell centering, then I
collimated and performed the star test.
The inside and outside diffraction patterns are not very good, therefore I
am arguing if the loose secondary cell is responsible for that
unsatisfactory
performance.
Any suggestion on how to check again and correct those issues will be
greatly appreciated.
Antonio Zanardo
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| Guest |
| Posted: Mon Apr 21, 2008 3:37 pm |
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On 2008-04-21, Antonio Zanardo <antoniozanardoTOGLIMAIUSCOLE@ATlibero.it> wrote:
Quote: The central screw retaining the secondary cell of the scope became loose,
thus the cell was turning around and moving from side to side as the
corrector plate hole is a bit larger than the cell..
I tightened the central screw without checking the cell centering, then I
collimated and performed the star test.
The inside and outside diffraction patterns are not very good, therefore I
am arguing if the loose secondary cell is responsible for that
unsatisfactory
performance.
Any suggestion on how to check again and correct those issues will be
greatly appreciated.
The secondary must be centered to have satisfactory
performance. Re-center the secondary (measure carefully)
and re-collimate.
Bud |
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| Roger Hamlett |
| Posted: Tue Apr 22, 2008 5:17 am |
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Guest
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On Mon, 21 Apr 2008 15:37:22 -0500, wrhamblen@comcast.net wrote:
Quote: On 2008-04-21, Antonio Zanardo <antoniozanardoTOGLIMAIUSCOLE@ATlibero.it> wrote:
The central screw retaining the secondary cell of the scope became loose,
thus the cell was turning around and moving from side to side as the
corrector plate hole is a bit larger than the cell..
I tightened the central screw without checking the cell centering, then I
collimated and performed the star test.
The inside and outside diffraction patterns are not very good, therefore I
am arguing if the loose secondary cell is responsible for that
unsatisfactory
performance.
Any suggestion on how to check again and correct those issues will be
greatly appreciated.
The secondary must be centered to have satisfactory
performance. Re-center the secondary (measure carefully)
and re-collimate.
Also, rotate it back to it's original position.
There are index marks on the back of the secondary, which give the
orientation. The primary and secondary rotational orientation, is not
'hypercritical', but on assembly, the secondary is placed at
approximately the 'best' roatational orientation, so that some of the
errors on the secondary and primary cancel one another. If it is badly
out of rotational position, you may find the scope performs 'below
par'...
Best Wishes |
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