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Help required please.


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Due to an extremely clumbsy and annoying (kicking myself) accident, I have seriously knocked my scope out of collimation. Every thing now appears at 45 degrees sloping from right down to left.

I have only had to tweak my scope before and haven't really had to do a great deal with it as far as the secondary mirror goes. I have attempted to rectify things but to no avail.

Seriosly getting me down now as I cannot seem to sort it out.

Any advice or suggestions will be greatly appreciated.

Edited by Ewok
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If you could post the make and model of your scope and some pics of the secondary mirror we can probably post some suggestions of how to sort things out.

We've not got too much to go on at the moment :)

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post-22912-133877540637_thumb.jpg

Here is a photo ( not too good I know ) of my secondary mirror.

I thought it looked OK, i.e central and non eliptical etc.

By the way my scope is a Celestron AstroMaster 130eq.

Any ideas ?

Edited by Ewok
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That does not look to far out to me. Have you star tested the scope ?. That would quickly show whether or not the collimation was miles out.

You said in your 1st post "Every thing now appears at 45 degrees sloping from right down to left." Could you explain a bit more what you mean ?.

If every thing is sharply focused but tilted to one side then it could be that the scope has just rotated in its tube rings.

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Basically the horizon is now like this / . I have tried moving the scope around in the tube rings and the image still remains on the slant. I have tried rotating the secondary also, this isn't the issue either.

It never used to be like this, only since I dropped it ( still hate myself for that ).

According my cheshire and colli cap the scope should now be almost perfectly collimated, images are sharp in focus, but all at 45 degrees or so.

Some may say live with it as it is but I really want this to be right. :):(:p

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I think you may need to open it up Martin and check you haven't broken a mirror mounting bracket - the pic of the primary looks more then out of collimation and would deffo explain the tilt when looking through it. Sorry mate - it ain't looking good. :)

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Hi Brantuk,

The thing is everything appears to be collimated well. Are you saying that the primary mirror may have broken a bracket ? The pic I have posted is of the secondary just to show that it is centered and round in appearance.

In my original post I said I had knocked my scope out of collimation, I have now re-collimated and should be fine.

Surely there must be some explanation for the angle of the image being so severe?

Edited by Ewok
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Scratch what I said Martin - apologies I thought it was the primary (bit dozy this morning lol). If that's the secondary through the focuser tube then it should appear round and concentric.

It looks slightly at an angle to me cos of the sliver of shadow on the left side of your pic. The bump may have twisted the secondary slightly.

On the other hand - if you're sure the secondary is straight then that could be a reflection of the primary which looks down on one side.

You might be lucky and just have to twist the secondary straight. If not then an inspection of the primary seating is what I'd do. Hope that's a bit more helpful :)

Edited by brantuk
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Thanks Brantuk, all sound a little bit daunting. I have tried rotating the secondary about to rectify the problem, with no luck though.

I geuss I will just have to persivere with it , if no joy I will have to get a proffesional to look at for me. :)

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Yeah - it sounds daunting if you haven't done it before - scared the heck outa me when I opened up the primary cell of a scope for the first time. But actually it's dead simple - it's just a disk clipped on three mounting points lol.

The main thing is to be sure you don't touch the mirror surface or get anything on it. Other than that it's just three screws - very basic. You'd easilly spot if a bracket is slipped or broken. The hard part is getting it back in place in perfect alignment.

I usually mark the base plate and tube with sticky tape or a felt pen so I have two points to align to when reassembling. But if you ain't confident - is there a local astro soc who can help?

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I'm not sure if my eye is reflected perfectly central to be honest, thing is I'm at work now and can't check.

I may be able to seek advive from the Bradford Astro Society if all else fails.

May sound a bit silly but I really wanted to sort out this myself , probably because I know I created the problem anyway.

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Although your collimation may be out if the images that you see are sharp then it's probably not that bad.

Does the 45 deg. angle you mention relates to the difference in your eye level and the tube - if you image a horizontal line across your eyes (think of a long ruler sitting on top of a pair of glasses) now adjust your head so that this ruler would be parallel to the tube, this should make the horizon that you now see appear level - does this fix the problem?

EDIT...I've just had a proper look at that picture you uploaded, the secondary appears to be slightly rotated as you can see a marginally thicker mirror edge on the bottom, compared to the top (or this could be the camera not being central). But then when I look at the image in secondary I can't work out what I am seeing - I can see the right hand mirror clip, but what is that in the middle of the image? this is where I would expect to see the central doughnut. If you reduce the tensioners on the primary mirror are you able to tighten up all three sides of the mirror so that it is flush with the bottom(ish) of the tube?

I've pinched a couple of images from google that should give you an idea what to expect:

http://www.cloudynights.com/photopost/data/3105/9328Collimated-proof.jpg

http://starizona.com/acb/basics/images/collimation_labelled_out.jpg

http://starizona.com/acb/basics/images/collimation_labelled_in.jpg

Edited by xboxdevil
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Hi Steve, the image you can see is the secondary down the focus tube. The clip you can see is a clip retaining the mirror onto the secondary, not a primary clip ( if thats what you meant ?)

I can tighten up all three adjusters on the primary mirror, but I'm not sure if that is where the problem lies.

I see what you mean about the slightly thicker edge on the secondary, I will have to play with the secondary again I think.

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Keep trying, you'll suss it in the end.

Can you see the primary mirror clips and the central doughnut reflected in the secondary?

Did you try to play with the angle of your eye level compared to the angle of the tube?

Edited by xboxdevil
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