Why is exact aligning of the Corrector Plate and the Mirror cell necessary?
Posted 06 August 2010 - 01:47 AM
My question is what is the exact technical reason for this?
Posted 06 August 2010 - 07:23 AM
The corrector plate does need to be centered and flat relative to the mirror however. I don't even know if they do this well in China as I have seen several SN scopes where the corrector was off center a little.
The good news is that the corrector alignment is somewhat forgiving.
Posted 10 August 2010 - 06:55 AM
It is used to the best alignment to the primary mirror
This reduced coma and other things
So yes generally each scope has to be aligned with the marks to make sure everything is correctly seated.
Most manufactures will not sell you a corrector plate and require you to send it back to them for repairs.
Fife Lake, Mi.
Posted 03 September 2010 - 02:43 PM
a) that the corrector plate is symmetrical about the optical axis
this means it does not need to be rotated about the optical axis to any special angle
c) It is important that the corrector and the mirror are mechanically aligned (i.e. in alignment like the two ends of a cylindrical tube)
If this is so, then surely Meade should've just been able to sell me a corrector plate, so that I could just remove and replace my broken one. I would've been happy with that. Instead I had to either ship the scope all the way to Meade for repair or (as I did) buy a whole new replacement telescope.
I get the feeling I had to spend money unnecessarily.
Posted 03 September 2010 - 03:43 PM
Like matched optics.
All I can go by on this is what Ive read and have been told in the past.
Fife Lake, Mi.
Posted 05 September 2010 - 09:16 AM
Don't feel too bad. I don't think any manufacturer would sell you a corrector or mirror. They probably feel that most people would not be able to install it correctly and they are probably right.
The SN's have really great optics and is a great scope for astrophotography once you replace the stock focuser. There are also some mods you can do to the mirror cell to improve performance.
Posted 02 July 2011 - 08:55 PM
As with all Meade SN-8's the wobbly rack and pinion focuser assembly is just so bad that it had to be replaced. Few people who are serious about astrophotography or deep sky viewing do not replace that terrible focuser. I now have two of these duds sitting on my bookshelf. It seems that everyone just accepts that the end-users have just got to learn how to replace focusers, which coincidentally involves removing and replacing the corrector plate!
My question is, given that a half-decent focuser is so critical to a scope's performance (not only for photography) and given also that Crayford focusers abound in even cheap scopes, why oh, why doesn't Meade just put a simple Crayford in a Meade SN-8 and be done with it.
It would save hundreds of SN users having to do it themselves! Think of the great PR when Meade made the announcement. The market interest in Meade SN-8's, especially for photography, would greatly increase as a result, I'm very sure.
Posted 13 July 2011 - 05:03 PM
Hope this helps,
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