I know I did a few 'stupid' things initially...
and sorry I never came back to this thread.
A lot of things happened as I always mention, I am on Astronomy a very sporadic one!
pff
Just a short update:
July 2022 - I think - I have taken off the 'secondary' SCT focuser I used initially to make my own Solar Scope and replaced it with spacers and I believe it did focus better.
Since I am a sporadic observer/imager, I did not do much of it - as usual!
I now finally managed to add the Skywatcher Auto Focuser with Remote control to AR90/900, about a week ago.
Bear in mind this focuser bracket (one of them and the strongest) does NOT fit this and any telescope with same similar focuser- as I expected.
You have to drill 4 holes, as exact as possible - in fact I did mount the whole thing to try and get the correct 'drilling' points.
Check image and you see how much difference in holes position - good enough spacing actually - without weakening the bracket, which I have to say is quite strong.
Important to drill the main threaded diagonally opposite holes as exact as possible, because this focuser is actually held by ONLY 2 of the Allen bolts!
I then drilled the other two slightly larger to allow a minimal adjustment.
The good thing is that this focuser has a nice 'springy-actioned' joining cylinder - the one that fits the drive motor pivot to the focuser pivot.
I guess that should absorb any uneven movements and slight non-centred possible tightness when running.
I just taken lenses out cleaned, then checked D-ERF was still not-moving inside and re-fit lenses and I just also added a bit of Teflon tape to try and reduce Etalon tuning knob play a bit and it seems to do the job.
Also Auto focuser works well!
Looking forward for when The Sun is high enough for my point of view - possibly 2 weeks.
I wanted to test it today for the short time is visible 10:30-11:30, but the usual WRONG weather forecast.
I generally never believe them, in fact I did not take anything out - I get it more right by myself, as one has to learn to know their own area and forecast based on official ones!
I am in a semi-open valley.
☁☁☁