... some disassembly required!!!
Alas, these older OS scopes have no way to remove the rear cell / primary for cleaning. Consequently, cleaning in-situ after removing the front truss is the only safe way to go to avoid a lot of work and major collimation issues.
Quite a stressful thing to do in any case!! First I made sure the laser dot was on the secondary spot. Then I taped across the 4 truss blocks to make sure the front truss goes back on in exactly the same position. Then I took my time ..... and said a few hail Marys!
I unbolted and took the front truss off -
very slowly and carefully. I was afraid the truss would collapse when I removed it but thankfully the four truss pairs were quite stiff. Then I unscrewed the primary baffle and pulled out the primary shroud.
Sounds easy doesn't it? And it is if you've done it before - which I haven't!!
Now ready to clean the mirror (in-situ)!