Took a lead from Dennis and decided to capture an avi of a star test with my 9.25 tonight to check my collimation.
If it looks a little "earthy" it's because I used antares to perform the test. Hence the browny/red colour.
I can see from the final registax image that the collimation is almost spot on. Could do with a very minor adjustment. Move central obstruction down and to the right, which would see the airy disc shift up and to the left to a perfectly centred position.
I think that's right?
This image was taken with the ToUcam in a 2.5x Powermate for approximately 1175x
Took a lead from Dennis and decided to capture an avi of a star test with my 9.25 tonight to check my collimation.
If it looks a little "earthy" it's because I used antares to perform the test. Hence the browny/red colour.
I can see from the final registax image that the collimation is almost spot on. Could do with a very minor adjustment. Move central obstruction down and to the right, which would see the airy disc shift up and to the left to a perfectly centred position.
I think that's right?
This image was taken with the ToUcam in a 2.5x Powermate for approximately 1175x
looks pretty close to me Matt.At this mag you should be closer to focus to pick up collimation error better - that is smaller rings
by the way Matt I'd be calling the seeing as pretty good based on that image, I've taken avis of stars like this before and rarely do the rings show up so fine... maybe a 6/10 or better?
Yes Matt, I certainly know all about that fixation you mentioned. Me being me...I'm gunna make a point of purposely putting the SCT out of collimation & firing off a few to see the difference between good & bad collimation. I've seen the pictures on the internet; but I'm the type that needs to see it first hand. I want to know how far out it can be before it becomes an issue in high magnification photography.
That damn fixation gets me everytime actually!! Only last night when I dropped in the 2X barlow/diagonal/didgeredoo extension tube...& then had trouble getting focus....I stood back & thought "hmmmm I wonder if collimation ISSS really on the money!??"
I almost had to physically restrain myself from grabbing the damn screw driver & having a tweak! I KNOW it's on the money, damn it!
Collimation like that image of Antares, I would say what ever you do
DO NOT TOUCH IT!
You will not see the difference in the focussed image. Its called splitting hairs, chasing rainbows. But if you gotta do it to put your mind at rest then because its a free world, go for it.
As a well known prophet (who lives down the road) once said. Seeing rules.
Matt, collimation is a bit like seeing in some respects. By that I mean if the seeing is only mediocre then having your collimation out a bit isn't going to make a hell of a lot of difference. The better your seeing the better your collimation needs to be to make the most out of it. I agree with what has been said before that you need to use less out of focus to judge correctly, though from looking at your image personally I would be trying to tweek that as you said, to the right and down.
It's also very important to have the image/star as close to center of your chip when judging collimation as you can get it. Are you collimating with or without a diagonal?
I've found a pretty good estimate of accuracy of collimation is if the star is flaring out one side more than the other. If it is then you are not collimated yet. On nights of poor seeing I will sometimes use that flaring to judge collimation if I can't get rings. If I can get the flaring even around the star then I should be pretty close to collimated. Certainly good enough for the conditions. In fact in those sort of conditions I will probably be saying, "what the hell am I doing out here wasting my time "
Also do you suffer from a "Blue" rim on your images after you process, or when you're imaging is one side showing blue flaring? I've found that can also indicate a collimation issue, but not on all nights it seems to depend on the humidity at the time.
The Jupiter/registax screen shot was just my way of saying "my collimation is NOT perfect, but I managed to capture this bloody shot, does it look ok to ya?"
Happy with Lesters last jupiter efforts? I collimated his scope too...well we both did really
Me being me...I'm gunna make a point of purposely putting the SCT out of collimation & firing off a few to see the difference between good & bad collimation. I've seen the pictures on the internet; but I'm the type that needs to see it first hand. I want to know how far out it can be before it becomes an issue in high magnification photography.
, that would be it
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