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Old 17-07-2013, 05:23 PM
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graham.hobart (Graham stevens)
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Maxim DL 5 LRGB stacking errors? what

Hi, I took these files last night - auto guided with Maxim as well and dither via guider set.
As you can see there are spots on the colour filters which are not really there in LUM, and as they stack it comes out in a line of dots all over the place. I can't work out what is wrong. Balance and guiding seemed to be good and I autocalibrated with darks done straight after the LRGBHA etc files.
(No flats though)
Help!!
Graham
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  #2  
Old 17-07-2013, 05:41 PM
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graham.hobart (Graham stevens)
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Maxim Dl stacking errors

One thing I forgot to mention (well two things) is the camera is a QSI 683 and I recently started using a PMX ,so the camera and the guider are plugged into the USB ports on the mount itself, and the cables ar bunched and tied all together at one point- this may be significant as I never noticed this pattern on previous LRGB frames when the cables were separate and straight to the laptop. ? interference?
But as said I don't really see it on the lum frame. (frame 7)
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Old 17-07-2013, 06:02 PM
cfranks (Charles)
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Those spots are your Hot Pixels and the line of them actually is the same hot pixel moved to a different place on the image by the dithering making it easier to get rid of then with calibration. This is why dithering is done. You have to calibrate the images (bias, darks and flats) before you stack. It looks like the Lum image has been calibrated. I have the same camera and mount and my USB cables are bunched together with no problems. Sorry if I'm 'teaching granpa to suck eggs' as it were but that's what it seems like.

Charles
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Old 17-07-2013, 06:29 PM
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graham.hobart (Graham stevens)
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maxim Dl stacking errors

Cheers Charles- no worries about sucking eggs-
I actually thought Maxim auto calibrated all the filter shots as well as it was set up to do so. I will have to check.
I ticked the auto calibrate box -
will have another look.
At least it's something simple
Many thanks
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  #5  
Old 19-07-2013, 10:37 AM
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graham.hobart (Graham stevens)
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maxim issues

I changed the stacking protocol to Sigma or median and it solved the issue- apparently this is better for avoiding hot pixels!
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