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Old 05-08-2011, 09:42 AM
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troypiggo (Troy)
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dithering versus flexure

This could be a dumb question, but what are your thoughts on the effectiveness or usefulness of dithering if you're using a guide scope where you (will almost always) get flexure to some degree. I would think that the effect of the flexure would basically do the same thing, although not as elegantly?

I had some seriously bad flexure, way too much, and I know that's not a good thing. Think I've solved that so that while it still does exist, it's minimised as good as I can do for now. I intend to do some testing to actually measure pixel/min, but the results from Astrofest seem promising.
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Old 05-08-2011, 10:02 AM
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multiweb (Marc)
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Quote:
Originally Posted by troypiggo View Post
This could be a dumb question, but what are your thoughts on the effectiveness or usefulness of dithering if you're using a guide scope where you (will almost always) get flexure to some degree. I would think that the effect of the flexure would basically do the same thing, although not as elegantly?

I had some seriously bad flexure, way too much, and I know that's not a good thing. Think I've solved that so that while it still does exist, it's minimised as good as I can do for now. I intend to do some testing to actually measure pixel/min, but the results from Astrofest seem promising.
Technically, dithering will only work if you have a sharp sub. Flexure does the same to your background as what you see in the stars. It's smeared. So flexure needs to be sorted out. Flexure is a no-no. Then you can dither if you want.
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Old 05-08-2011, 11:31 AM
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troypiggo (Troy)
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Cheers mate. I know the flexure is a no-no and trying to get rid of it, but seems that with a guide scope setup, as opposed to OAG etc where imaging scope is also guide scope, you're going to get at least some flexure. Understand the difference a bit more now to dithering.
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Old 05-08-2011, 01:34 PM
jase (Jason)
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I think the question here is how predictable is the flexure. If you know its will flex a specific way time and time again, then its performing the dithering for you. Reality is however that flexure is going to be more severe as the scope points to different areas of the sky. In addition, there will be some subs taken where minimal to no flexure is present. Dithering on the other hand is predictable. It will move the scope a specific amount (as configured). Flexure or no flexure, I would be enabling dithering.
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