Another collimation help needed from a not so newbie

[spaceboy]

Hi All

I have to admit I have been winging it until this point but I think it's about time I asked for some advice.

I have no issues with collimation itself as such but after picking up on some odd result from star test I am beginning to doubt my focuser alignment skills. It seems there is an abundance of collimation how to's but not so many on aligning you focuser square so as not to compensate in the misalignment through the secondary position /tilt.

I have checked my optics for pinching and all is OK there. I admit that the primary may not have cooled to the best temperature but I have not seen this kind of star test error before when the mirror has been warm so there is clearly something not perfectly aligned. Collimation looks good and for the best part there is no obvious effect on the views but I thought I may as well ask how others align their focusers as this may well be the problem and it doesn't hurt to know for the future if I make any upgrades to my focusers.

Any advice or direction to links welcomed.

SPACEBOY

[Tinker1947]

I always thought you used a film canister cap with a tiny hole in it and then adjusted the secondary mirror so the primary mirror clips were all in view and even around the edge. this put the secondary where it should be.....

[spaceboy]

That's to align the secondary to the focuser but if the draw tube isn't square on all your going to end up with is tilts in the secondary and primary compensating for the tilt in the focuser. My guess if this is too much of a tilt then your going to end up clipping your aperture at some point??

I can get what appears to be perfect collimation using a collimating eyepiece with a tilted focuser as I have done so in the past only to then see the issues in a star tests. Great when the skies are clear long enough to have a mess to put it right. I have successfully made an artificial star out of an led torch which is great for checking collimation but the longer the focal length the further away I need it and I only have a modest sized living room