Collimation tangles

[beren]

With Paul mentioning collimation i thought i would tweak mine , i have bobs knobs installed on mine and the last 3 times ive adjusted them its been fairly easy to get good results .Going into it with confidence i tightened all the knobs before adjusting for safteys sake , racked out the focus and proceded to ........get frustrated , even with my reference http://home.att.net/~starastronomy/Astrophotos/Articles/SCT-Collimation/sct-collimation.html

i encountered difficulties , the image presented through the eyepiece was a cone like shape and every adjustment was poving fruitless . After a while , i walked away collected my thoughts and started from the begainning and remembered the basics . Being confident for quick results i didnt rack the focus out to get a decent sized dounut shape and taking it easier with the adjustments and being patient .lesson learnt and collimation sweet now ....im :)

[gbeal]

It is a b$%&*#r of a procedure sometimes isn't it? Maybe try it with a ToUcam on the monitor?
Gary

[rumples riot]

Stuart, getting good collimation is easy, getting great collimation for planetary work is very hard. It can be extremely hard to get that last little bit. I have spent weeks trying to get the best possible collimation.

One tip that I can give is when collimating a SCT ensure that you move the focus adjustment in a clockwise direction each time you go in and out of focus. Meaning that if you have to go anticlockwise go further than needed and then come back to where you want with a clockwise focus. The reason for this is that the mirror assembly goes slack under a anticlock wise turn and a clockwise turn takes out the slack. If you don't follow this procedure each time your collimation will be out and you will decollimate your scope.

The other thing to bear in mind is not to tighten the secondary knobs too tight. You might crack the corrector plate or damage the assembly which the secondary works on. That has not happened yet, but one must be mindful of it.

My collimation is still bothering me and I am begining to wonder if my secondary has a best mean fit for collimation. Meaning that the optical axis is slightly out and that Meade just meaned out the error to get a good collimation. If that is the case, the scope will have to go back and have a new secondary fitted before my warrantee expires. There is a test I am going to do today to determine if this is the problem.

Anyway glad you got your scope collimated Stuart.