Hi Again,
Yes its time to contemplate the line to the shop /distributor : "If you cant collimate this scope after replacing the secondary mirror and fixing the focuser tube (and charging me for it), then perhaps you should replace it with one that works or refund my money"......
I picked up the scope from the repair centre at the distributor and spoke at length to the guy who "collimated" it and he assured me after I looked into the focuser and saw mirrors half obscured, that all was in perfect collimation.........
He showed me a red LED mounted on a piece of board that he placed in the warehouse about 50-100m away that was used to collimate the scope and said this is the best way to do it. I was skeptical and it appears now with good reason.
The focuser tube was repaired as the excessive slop was caused by incorrect packing around it and this seems to be OK now. I brought the scope home after paying for the replacement of the secondary chipped mirror and the collimation and thought I would grab a look at the stars on Friday night.
Well.... Can anyone guess what happened?
Yes, as expected the star test showed up SERIOUS miscollimation to the point of not being able to get a pinpoint star at any point of focus and flaring of the star either side of what should have been focus which looked like a soap bubble enlongated on the right side. After resisting the urge to head to the shed and pick up the sledgehammer (seriously, I had to stop myself), I took it back inside with much cursing, and put my cheshire in again and shook my head again and cursed some more.
At least this time, I knew what I had to do and how to do it and tried to get some collimation happening.
I managed to take out the primary mirror cell from the end of the scope and correctly and accurately put a centre spot on it (using a foolscap hole reinforcement sticker) and then assembled everything back together. After a test on Saturday night on the moon and a few stars at dusk I was a little closer to correct, but found my star tests still showed up some issues, namely non concentric flaring off focus. Certainly a quick squizz at Saturn had me cursing some more as I could not achieve a focus at 200x at all and at 80x I had some ghosting.
Well today (Sunday) I pointed the scope out the window to the bright daylight sky and tweaked and tweaked and now think I have achieved as close a collimation that I possibly can.
I have ALL three primary mirror clips within view, a ROUND image of the primary, a concentric circle around the outside of the view of the primary (from the reflected 45 deg silvered bit of the cheshire) and concentric secondary reflection AS WELL as FINALLY getting the centre spot on the primary concentric to the whole thing. (something I havent been able to achieve before as it had no spot on the mirror and I can see why this could have been a missing jigsaw piece before) The crosshairs of the bottom of the cheshire line up EXACTLY with the secondary vanes and everything is as centred as can be expected. NOTHING looks out of whack, even the secondary's holder is not skewed or off to one side but is now centred within the view.
All that is left now is to hope these clouds disappear tonight and I can test the view AGAIN
I
cannot possibly conceive
anything wrong in ANY respect with the mechanical alignment of the equipment. Every aspect of the optics are aligned along the centre of the view through the cheshire and all "looks" perfect. Certainly it all looks better than I have EVER seen even before I started this nightmare a month and a half ago.
I have reviewed every collimation document on the planet it seems and the instructions of the cheshire and the Skywatcher manual itself and have followed them all to the letter. I have done this so many times now I am thinking of starting a TAFE course and charging others for the priviledge.
I would have definitely expected that the scope was to come back from the distributor repaired to factory precision and it certainly wasnt, so I am going to be getting a refund for the collimation charge ($40) tomorrow. I will live with the secondary mirror charge ($20) as my tinkering caused the damage there.
If the star tests tonight (weather permitting) are unsuccessful, then I am going to be lobbying to the shop and the distributor to return the scope and the tripod and get a full refund because this is getting BEYOND ridiculous.
If ANYONE can find any flaws in my methods, please post a reply to this post urgently as I am of the belief that I have done everything exactly as it should be and if the collimation is still not working then I think I have a lemon. Plain and simple.
Wish me luck....if there is any left.
PS. I have plagiarised two of Don Pensack's collimation images from his guide to show you what I had before I had the primary mirror spot was put on (image 1) and what view I now have (ignore the laser triangle as I dont have one of those)
Cheers
Chris