Because my MTO-1000A suffered from what I believed was slight astigmatism, I decided to do something about it.
So I went googling and found many web-pages on the subject, suggesting this was because the glass was stressed by over-tightening retaining rings...
Now, after dismantling and relaxing the stress to the optical parts, the problem remained the same in nature, however significantly worse in magnitude.
Now I am wandering if the original problem was caused by pinching/stressing of glass at all....
The brief description of star image as the focus is moved in and out is as follows:
Out of focus: slightly elliptical ring is visible.
Closer to the focus: elliptical ring becomes sharper, and very narrow.
Focus: Cross-like shape is visible
Out of focus, other side: Elliptical ring is again visible, however orientation of axis is 90° compared to other side of the focus (what one would expect from astigmatism).
I suspect the scope went out of collimation somehow (but how, it is beyond me.. unless I bent something while dismantling.. which is not easy considering the heavy mechanical design of the scope).
I tried to find suitable optical simulation software to determine what may have gone wrong, but it seems all the packages available to me (Oslo, Modas, Linos, Atmos) can not deal with lateral misalignments and/or tilt of optical components of the system.
I am determined to fix this problem this or that way.. at least I want to have the same situation as before dismantling. It is a matter of pride now !!!
Anyone has any ideas or similar experiences ?
Edit: image attached (Mu Cruci, focal with 400D), to illustrate the problem better. This was the situation before dismantling.. now it is 3x worse...