I don't think it is the bow tie (but I used to wear those a lot!).
If you're using the iterative method, it could indeed be a close jumble that resolves into two axes that intersect at the ROC. This would look
like a perfect stack, but would not agree with the Blug (which would show the residual primary mirror axial error). If you correct the primary with the Blug, the autocollimator will again show a close jumble, which you can further reduce by adjusting the secondary (and if you get a "perfect" stack, it's actually quite likely you've realigned the axes again so they intersect at the ROC!) Each iteration reduces both axial errors until both tools show "perfect" alignment.
If you carefully decollimate the primary mirror first
, and stack the fainter inverted reflection with the front most upright reflection, you zero the focuser axis first
. and you can then align the primary mirror without affecting the focuser axial alignment--one step!
Vic, I have wondered why many times. My scope is a 10" f4.9
That's a more generous tolerance than f/4.7. At f/4.9, the primary mirror axial tolerance is 0.65mm or about 0.025-inch (0.05-inch tool tolerance).
I would imagine that my triangle is a little off, but not by much.
Even if it is off--it won't affect the tool alignment.
Now could the actual focal center of the mirror be off.
Although that would affect your scope's performance, it has no impact on the tools.
Bought Vic last book and try everything I can think of...
Did you try the carefully decollimated primary procedure?
...so I think I am just going back to blugging it.
If you can't
get the tools to agree, and you've verified the Blug by rotating the Blug in the focuser drawtube, you should use the Blug result until you've resolved what's impacting the AC alignment.
But this stuff is interesting to say the least and frustrating at times. Once I get all four little images lined up, I will take the AC out and check the blug and it is off. When I put the AC back in without doing anything, it is off again.
Without doing anything
? That sounds like a registration issue...
Could I have gremlins in the scope?
Unless you've already exorcised them, it's a given with most assembly line scopes! Looks like you've already addressed the optics--but the compression ring in the focuser could be a problem, and two locking screws can play havoc with the focuser axis...