[APML] Cassegrain Question

[William Mattil <wrmattil@ix.netcom.com>]

Gentlement,

I have a rather dumb question regarding a Classical Cassegrain.

Assuming that the secondary support mechanism is centered within the OTA
(I realise this is a big if :^) ) and the rear cell is in place, no
optics installed. If a laser is placed into the focuser shouldn't the
laser exit through the central hole in the secondary ? It seems to miss
by a large margin and only by wedging the rear cell a bit can I make
this happen. Furthermore the focuser cannot be shimmed due to the design
(this bothers me a bit). With the rear cell wedged, the support bolts
cannot be fastened due to the missalignment.

My initial thoughts are that collimation would be a bit of a waste until
I can get this aligned a bit better. Am I way off base here ?

Any thoughts or on-line sources that could clarify this for me would be
greatly appreciated.

Best Regards

Bill

PS: Star Instruments 10 inch f/15 Cassegrain

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