Andrew,
Bases on the elongation in post 30, ill say the elongation is 2 pixels diagonal. so this is 25 micron for 9 micron pixels. with an image scale of 0.73 arcsec / pix, this gives 2 arcsec of elongation. my guiding is typicaly -/+ 0.3 pix and with an image scale of 1.2 arcsec / pix this guides to 0.72 arcsec.
So, the logged error in guiding is much smaller. but having said that, the guider monitors the star centroid not the whole star profile. these elongated images still have a centroid. this would suggest the guiding is still accurate...??
Is What your suggesting that the main imager chip is insecure? If i get a shot through the guider chip and it showed the same star elongation, then that would suggest its not the camera chip - I can do that.
Josh
Quote:
Originally Posted by alocky
Fair point- but that means your guiding performance must be a red herring. How does the size of the star elongation compare with the logged error in guiding? If they're comparable, then yes, any element in the system could be your problem. If the guide log is telling you that the image should be better than it is, then the problem is restricted to the part of the system where there can be a difference between imaging and guide chip.
I'm sure I'm not adding anything you haven't already figured out here....
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