Sounds good, and should work well, but, once you center the secondary to the baffle, skip further rotation of the corrector/secondary assembly.
I would check the centering of the bare corrector perforation first, then insert the secondary housing, align it by eye and then ONLY change the collimation screws.
That aligns 1) the primary and baffle opto-mechanical axes to 2) the optical and physical center of the corrector and, finally, 3) centers the corrector physically with the rest, at the same time centering it optically as well.
Your combined corrector-secondary method that you mentioned really should be close.
Once you have that, or if you just stick with the combined corrector and secondary centering you just tried (which should be fine I would think), DON'T further rotate anything. Rotation will shift the secondary out of the centerline. You will be ready to just collimate.
Just center everything, tighten it down, and do the REGULAR screw collimation (which should work without issues).
Since everything was taken apart, I highly recommend starting with the Robin Casady method in daylight, working from the secondary end, adjusting the screws until the reflections are concentric. See http://www.robincasa...ro/collimation/
It is a breeze if you sit in a chair at a distance that lets you match edges of reflections, with the scope in a cradle (I use a mitre box) or on a mount. Amazing how much easier it is when you are FACING the screws!
Only then do the out-of-focus shadow at night or on an artificial star. A small ball bearing in the sun at 100 feet is okay, but some 'artificial' SA might show up at that short distance, but can be ignored.
The Casady method should have you VERY close to perfect.
You are not done until you finish with collimation tweeks on a star in focus, preferably at night. The shadow method only gets close.
In my experience with mangled SCTs, the Casady method should MATCH the star method. If you check the Casady reflections after star aligning and one, or more, is decentered, you likely still need to tune up the optical and mechanical center alignments. After I move I will chart which misalignment moves which reflection edge, using my M8.
If the two methods are very close, you should be getting great images, assuming the usual good SCT optics. A ronchi or DPAC test will flag issues like zones, roughness, and SA. Astigmatism should show in the defocused collimation process.
The star collimation is the 'more correct' of the two if they don't match and you want to use the scope to observe.
My M8 is very close to matching the two methods, decently sharp (even with a bubbled secondary silvering), and was once uncollimatable and useless. It still needs a bit of tuning, but the Casady method almost matches the star collimation. It has a bad secondary coating, so it will await that fix.
My C11 was very soft but is now decently sharp, but the rotational alignment is off due to bad info online, and a secondary that was rotated during screw removal (the Fastar secondary holder has an alignment notch too), it should be extremely sharp once finished. The Casady method is still noticably off from the star collimation. I am across the country from it, so it may not be finished before I move.
If you are moving up from an 8", you should be amazed at the 10! I was.
I have wondered if Meade makes intentionally off-centered secondaries to allow them to match slightly tilted baffles by rotation of the slightly eccentrically glued secondaries.
The Celestron EdgeHD whitepaper appears to confirm these opto-mechanical axis alignment thoughts, and much was gleaned from the C14 efforts on wilmslowastro.com. The Faster/Hyperstar needs to start with a coincident axis scope before the extra FS/HS optics are added.
Edited by markb, 09 November 2019 - 01:45 PM.