Help collimating a doublet refractor

[assouptro]

Hi Scope buddies! 
 I have a confession.

I'm sure I won’t be the first or the last to do something stupid like this! 
 

I have an old revelation Astro ex 100 doublet that has served me well and is quite good for imaging 

just recently, I noticed some astigmatism slightly crossed shaped stars on one side, I thought it may have been tilt, so I introduced a tilt juster into the optical train and using Astap I attempted to correct it.

I couldn’t correct it and with it being particularly cold, I wondered if it might be pinched optics

So I thought I would back off the lens retaining ring.

This ring was really tight and I stupidly thought that the four screws round the outside of the cell might have been holding it in position

I backed off these screws and undid the ring then realised those screws were for collimating the lateral position of the cells! 

I had succeeded in making a good scope with a small issue into a useless scope with a big issue

I’ve been reading about refractor collimation, and it appears to be “fairly straightforward” especially as it’s only a doublet, and I also understand getting the focuser  Square is critical 

I have used my OCAL camera resting on top of The, Cheshire eyepiece to produce a couple of images of the circles that I am looking at

Depending on the angle that I shine a light into the Cheshire, I get varying reflections

What I want to know is, should I be looking at the tiny circles in the middle

 

Tiny Circles 

or the slightly larger more easily defined circles? The second image.

Bigger Circles 

If all else fails, I will just have to send it off to somebody who knows what they’re doing! 

Thanks in advance for any help
 

Bryan (the numpty) 

Edited February 11 by assouptro
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