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Old 08-03-2008, 03:17 PM
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leinad (Dan)
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leinad is offline
 
Join Date: Feb 2008
Location: Perth, WA
Posts: 1,307
Firstly, Thanks all for your input.

Collimated the scope today and I must say it was waay off the previous few weekends viewing.
At low magnification this wasn't really noticeable, but I can see now that at higher magnification the view was blurry and now I think it would have been a lot better(clearer at high mag.) if the scope was properly collimated.

By loosening the secondary mirrors 3 screws I was able to rotate /adjust the mirror so that through th focuser I could see the primary mirrors three clips. Then by using my Skywatcher collimating piece I was able to fine tune this by slowly tensioning each screw.

then using the laser collimator I fine tuned the screws again to line the laser with the ring on pri mirror, then adjusted the pri mirror.

Notes on collimation process with laser and skywatcher collimator tool.

1) The laser had quite a bit of wobble in the focuser, and after wobbling rotating the laser in the focuser I was able to ensure that the laser dot was as close to center rotating around the pri. mirror ring circle.

2) the Skwatcher collimation tool was much better in viewing the collimation alignment of mirrors. bit of a disappointment with the wobble of the laser in the focuser as it could never be perfectly held in the focuser.

3) Tried the barlow laser trick. am i supposed to check this reflection by looking at the pri mirror(this is where I could see th reflection.
the focuser tube in the scope didnt allow me to see the barlow end with the paper circle attached to the bottom.

I believe I've got the collimation as good as I can get, but I did notice that in order to see all 3 clips of pri. mirror in the focuser that when the collimation tool was in the focuser and looking through the pin hole, then reflection of the tool/diagonal looked offset slightly towards the open end of the scope.

Is this acceptable as long as the collimation looks all good?
Do Skywatcher 8" dobs have a slight offset like this?

Hoping it will be clear tonight to test the scope again, and see how much clearly Saturn is at higher magnification as well as other open/globular clusters.

see pic below of offset
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Last edited by leinad; 08-03-2008 at 04:06 PM.
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