Thanks Peter and Jase,
last night i ran some more tests and for a moment there i thought i found the issue. When i turned the cooling fans off on the scope, the elongation went (in a few images) then when i turned them on, (without slewing) the elongation re appeared. this was rather repeatable. However, then the elongation re appeared with the fans off. So that was like ....aahhhh, taking candy from a child.
I do believe however that running the fans made it easier to collimate while in focus. Dont know why but star shapes just settled down a little. weather this was due to vibrations or tube currents??? the scope had been cooling for hrs aswell before i found this out.
I think my collimation maybe shifting somewhat judging by the images i get from my defocused stars that i periodically check. however that sensitivity varies depending on how defocused you are, so i need to go back to the same position all the time.
I did the test for astigmatism at the zenith and there is some evident as the scope gets close to focus (focus is around 18400).
here is a dropbox folder with images at the zenith in the middle of the chip (file name is the focus possition). what does one make from these. Has anyone with anothe PW CDK seen similar results?
I did tighten up the spider veins before i started last night and some images were better, but still got some bad ones and in particular a horrendous one after flipping the meridian while pointing at the SCP. this is it
here. its only 10 sec so there isnt much data.
So in summary, i need to talk with PW agian. Im of the opinion something is moving and its not always repeatable - the focuser or mirror??? and i need to decide weather to send it back (after talks with PW) or work on it myself. the 12 month waranty has passed by nearly 2 months, but ive been working on this for 4 months, so ... i dont know. It would be really good to have another focuser that i knew would be sollid so that part of the train could be eliminated. I can flex the current focuser with some slight hand force, but thats pretty subjective.
thanks
Josh