Hi John:

Thanks for your post. You have solved a mystery for me.

I had always centred my secondary by centreing the corrector in the scope
end casting. Recently I discovered that a direct measurement from the
secondary holder to the end casting showed the secondary was 2-3 mm off
centre!

To date I have shimmed the corrector in position to get the secondary in the
centre of the optical path. I had never imagined that there would be
significant slop in the hole in the corrector that receives the secondary
holder.

I believe that a previous owner of my scope had tweaked and maladjusted my
2120 10" in every conceivable manner.

Once the secondary was centred the views improved.

Thanks again,

Richard Jordan


> I determined two factors here. First, the secondary should be centered. I
> found that there was quite a bit of play - use some shims to make sure it
> stays centered. I used some small thin plastic strips.
>
> Secondly, Meade told me (after a lot of interrogation on my part), and the
> rotational position is set to within 5 degrees when they do the alignment.
> That is, they rotate the secondary by 5 degree increments until the image
is
> "optimized". The didn't tell me what that meant. Also, after alignment,
> they do not put alignment marks on the secondary. I looked very closely
at
> the housing and the inside of the corrector hole, and found two matching
> impressions that appeared to go together. I placed the corrector in the
> hole at this point and tightened it up.
>
> I have no idea if this was as critical as either I or Meade thought. The
> images are fine, and everything is now tight and centered. I stopped
> worrying about it a year or so ago.
>
> Hope this helps,
>
> John
>

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