ATM Cassegrainian coudé: weird image at focal plane

[Bernard Maugoust <maugoust@free.fr>]

Hello all,

Before I post a detailed request which is bound to be longish, I'd like to be
pointed to some related archived thread if it already exists.

As said in the subject line, the scope is a Cassegrainian, 'coudé', so as to
fold the optical path into the altitude axis of an azimutal mount by means of
a third flat mirror (and thus not piercing the primary). 8" BTW.

The problem in hand:

Although every single part has be checked and reckoned fit for the job (3
mirrors, eyepiece, and mechanical pieces), when all is assembled, the focal
image has a *very weird* aspect.

For this check, no baffling at all was installed inside the tube.

Can anyone remember ramblings on this topic?

Failing this, and depending on whether offers for help turn up, I'll send
details.

TIA, and cheers

Bernard

-- 
Bernard Maugoust 3°59'E 44°28'N