Old 13-08-2012, 11:55 PM
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Carl is offline
Join Date: Apr 2006
Location: Alans Flat
Posts: 373
streaky star problem re visited

Just checked all of my subs and they have oval stars to one side.
This problem has only occurred since i rotated the focuser to suit M20 composition.
My earlier post stated that i also had a meridian flip and the streaky stars were only in the subs taken when pointing west.
I have left the focuser at the same rotation to suit m8 and now notice that regardless of a meridian flip i have streaky stars to the same half side of my image both taken at east and west.

I have done a meridian flip before and had absolutely no problems

completely lost


scope is a ed 120 with moonlite focuser
all mounted on an eq6 pro mount
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Old 15-08-2012, 11:08 PM
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whzzz28 (Nathan)
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Location: Brisbane
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Originally Posted by Carl View Post
now notice that regardless of a meridian flip i have streaky stars to the same half side of my image both taken at east and west.

scope is a ed 120 with moonlite focuser
Can you possibly post an image of a exposure before and after flip?

If it is only one side of the image, and the other side is sharp then it sounds like your scope/focuser is out of collimation.

An example of an uncollimated refractor (elongation on the right side): http://core-au.net/astro/old/camera/1100d/1600-200.jpg

If your images sort of look like this then the first thing i would check is that all imaging equipment is sitting flush to the focuser. Next make sure the focuser itself its attached firmly and evenly to the scope. Take it off and put it back on if need be.
Failing that, you will need to collimate the scope.
Refractor collimation is normally done with a Cheshire eyepiece and most/all moonlite focusers can be collimated. You may need to email Ron at moonlite to ask for advice on it, or see if moonlite have any documentation on doing it as i have never had to do it myself.
If the moonlite can not be collimated then you will need to collimate the optics, which can be difficult. I've never done it so i can't help you with that part.

If in doubt, post an image and we can take a look.

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Old 16-08-2012, 10:12 AM
Poita (Peter)
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The other possibility is that the CCD isn't quite mounted square. An image and full gear list will help sort it what may be causing it.
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