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Old 01-06-2015, 06:00 PM
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gregbradley
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In both cases (with and without the ONAG) the AO-L was used, the difference is only visible versus NIR guidance.
I think the text could be clearer on this matter, thanks for the question I'll complete it eventually.

I agree that the first image shows some elongated stars too, guiding at 14 degrees over the horizon was quite challenging even with the AO-L enabled, this is a bit an extreme situation.
Obviously I would not recommend to do so, the target was chosen so low above the horizon to test the seeing effect on guiding with visible and NIR under bad conditions.
But even if you correct for the star elongations there is still a significant difference using visible or NIR for auto-guiding (same scope, AO, and target).[/QUOTE]

I thought the same thing actually. It would be better to show a round star image from both systems with the one using the ONAG tighter stars than the obviously reject standard of the first. That matches how advanced imagers image.

See, an image like that first would be rejected by most advanced imagers when stacking subexposures and they would never image an object at 14 degrees above the horizon either.

I think the bulk of the public interested in an ONAG would already be getting round tight stars with their setup and would be looking to tighten that up even further in the neverending quest for better and better images.

Your ONAG and your focus systems sound like a way of doing that especially in conjunction with an AO unit it may well be the best of both worlds.

Greg.
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  #42  
Old 01-06-2015, 07:23 PM
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Quote:
Originally Posted by gaston View Post
Fair comments Peter,

In both cases (with and without the ONAG) the AO-L was used, the difference is only visible versus NIR guidance.
I think the text could be clearer on this matter, thanks for the question I'll complete it eventually.

I agree that the first image shows some elongated stars too, guiding at 14 degrees over the horizon was quite challenging even with the AO-L enabled, this is a bit an extreme situation.
Obviously I would not recommend to do so, the target was chosen so low above the horizon to test the seeing effect on guiding with visible and NIR under bad conditions.
But even if you correct for the star elongations there is still a significant difference using visible or NIR for auto-guiding (same scope, AO, and target).
I appreciate your clarification, just the way it was presented it seemed like you were not using the AO-L in the first image.
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