I have acquired an early 2000's Officina Stellare (A&M) RC-360AST (360mm F/8 Astrosib LK5 optics), with 2 element Riccardi field flattener. It's mounted in my observatory on an AP1200.
Initial analysis showed the collimation to be well centered with little coma or astigmatism.
However, the plate solved focal length is 3050mm, rather than the expected 2880mm, and focused stars seem a little soft.
I have purchased a licence for SkyWave CT, which confirmed the good coma/astigmatism, but says the spherical error is fair/marginal and negative (screenshot below).
I don't have a manual that explains how to adjust the secondary. There is a knob at the very end of the secondary (see red arrow), and I have the tool for turning the knob. Before I start adjusting things and mess up the current sitution, does anyone know what approach to take, and which direction to turn the knob? I think I need to increase the mirror spacing.
Thanks in advance for any insights!
Links to hi-res images:
Screenshot: https://drive.google...iew?usp=sharing
Scope: https://drive.google...iew?usp=sharing
