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Hi Rogerg
I agree that setting up orthogonality is a problem with the SCT telescopes. The method I use with the Meade telescopes requires skills that not everyone can use and workshop equipment that is normally available in a small machine shop.
The essentials of orthogonality are to first get the Dec Axis to be at rightangles to the azimuth axis by adjusting the height of the fork arms so that the orthoganality of the dec axis is within 30 arc seconds. this corresponds to a height variation of less than .05 of a mm. Very difficult to measure with accuracy let alone adjust.
The second step then is to get the Optical axis of the OTA orthogonal to the Dec Axis by adjusting the OTA in the tube saddles. This was quite easy when the OTA could be rotated right through the forks but extremely difficult with the OTA's that only rotate about 90 degrees.
I do all these adjustments with many variations to the method depending on the size and vintage of the telescopes.
I have been pressed into doing alignments for friends who bring their scopes to me with about four free hours of spare time and are able to assist in the heavywork. This was a free service but over the last year my stamina for this type of physical effort has deteriorated ( I'm now 75) and I can only advise while people do the work.
Regretfully Western Australia is too far away for a personal visit.
Barry
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