Synta 120/F8 Refractor Collimation

[dabsond]

I recently installed a new dual speed Antares focuser and 2" diagonal on my 120mm/F8 Synta Refractor. I think I am having problems diagnosing collimation problems. The focuser/diagonal combination gives great wide angle/low magnification views. When I use a 6.4mm or a 5mm eyepiece to check collimation I get a pretty strange pattern. After replacing the focuser I was expecting some minor tweaking to be needed. I am not sure what to make of this. I wish I would have checked it without the diagonal but I forgot to when I was checking. Please take a look at the sketch I have made and let me know what you think.

[GazOC]

Hi,

Are the 'disks' pulled out equally both to the left and right? Is it possible something is pinched?

As you said in your post, the first think to do is test without the diagonal in. You don't want to be pulling the scope apart when its something as simple as the diagonal.

Gaz

[dabsond]

I just got inside from checking it again. I think pinched is the right term. I readjusted the collimation screws to half position. Then working with a cheshire tube I slowly brought it pretty close. A quick star test proved it is very close to perfect. Clouds rolled in at that point, not before I got a peak at Saturn though.