Author Topic: Mosaic Problem  (Read 2401 times)

Offline Robert Q. Kimball

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Mosaic Problem
« on: 2016 September 09 15:20:31 »
I have been using PixInsight for at least two years.  Last night I used SGPro to image my first automated mosaic.  I pop the two images into PixInsight, and used StarAlignment->Register/Union - Mosaic to combine the two images.  I have done this before with no problems.  This time I got a nice combination, but the two halves were very different in their stretch.  Any thoughts?  The other strange thing is I'm using the same Atik 383L OSC camera but using SGPro I had to use a different Debayer setting than I normally do.   Here is a link to my mosaic:

https://www.dropbox.com/s/oat8h4aaesfzmja/Mosaic.jpg?dl=0


Offline pfile

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Re: Mosaic Problem
« Reply #1 on: 2016 September 09 17:07:20 »
it's not unusual - there are some things you can try:

1) did you check the "frame adaptation" box in StarAlignment? without that SA will not attempt to match the brightness between panels.
2) even with frame adaptation, sometimes things still look wrong due to gradients; you might try running DBE on both images before combining to make sure they are gradient free
3) there's a script out there called "dnaLinearFit" (by david ault) which will compute the intersection between two panes and run linear fit on them. this together with DBE should guarantee that your frames have similar background brightness when going into StarAlignment.

rob

Offline chris.bailey

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Re: Mosaic Problem
« Reply #2 on: 2016 September 10 01:06:24 »
The other strange thing is I'm using the same Atik 383L OSC camera but using SGPro I had to use a different Debayer setting than I normally do.   Here is a link to my mosaic:

Have you tried changing the co-ordinate origin of the .fits files in Format Explorer. SGP may well be writing the opposite of what you are used to. Its important that calibration and light files are taken with the same origin.

Offline pfile

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Re: Mosaic Problem
« Reply #3 on: 2016 September 10 11:43:04 »
that's a good point - if the calibration was bad one of the frames could be messed up.

rob

Offline Robert Q. Kimball

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Re: Mosaic Problem
« Reply #4 on: 2016 September 11 15:57:37 »
I started a new topic about my problem with more detail.  I tried all of the suggestion made here to no avail.  I do appreciate the help and suggestions.

Bob