Okay, these are my experiences “as is”.
Prior to using the OCAL Unit indoors, the M210 was in good collimation based on previous star testing and imaging results.
I then used the OCAL Unit indoors and made adjustments to the collimation based on the OCAL results. Test 01 is pre-adjustment and Test 02 is after adjustment using the OCAL Unit.
A couple of days later I took the M210 outdoors and performed a star test and found the collimation to be significantly off. This is poorly shown in a screen capture marked Test 03.
I then corrected this in the field and produced the attached intra-focus and extra-focus star tests using FireCapture SER stacks under less than average seeing.
When I then re-tested indoors using the OCAL Unit, I could not see any significant change to the OCAL pattern to alert me that “something had changed” as a result of my star test collimation in the field.
I was hoping that for the Mewlon 210, the OCAL Unit would be a killer accessory, much like the QHY PoleMaster where Polar Alignment is repeatable, definite and unambiguous.
EDIT:
I just added Test 04 Indoor OCAL Unit test after I had made collimation adjustments in the field based on star testing. I could not easily see an unambiguous change between OCAL results prior to the star test and after the star test.
EDIT 2:
Added an image using the Tak Collimation Telescope where I haven't yet quite worked out which ring/feature is what.
Cheers
Dennis