When to Debayer

[skeeloson@gmail.com]

Hello,

Very new at Pixinsight, so apologize for the question.

I have a DSLR with images exported as CR2.  The "Inside Pixsight" has been guiding me through the preprocessing, and it has been really helpful.  Using both the manual steps as well as BPP, I seem to get a rainbow effect across the final light integrated image sometimes.  From what I can tell, it seems to happen after I use the StarAlignment process.  My feeling is that it has to do with the debayer, and when its applied.  At what point in the preprocessing sequence do I debayer the images?  I could be totally wrong as well, so any other suggestions would be great.

Thanks in advance!

Scott Klein
Batavia, Il

[aworonow]

Scott,
  Think like a pixel. You are a red, green or blue one and you have perfectly corresponding pixels in each image raw image. If one image is shifted (before being deBayered) relative to another, as would occur in star alignment, then all the pixels of the same color do not line up, and the stack cannot be deBayered. So, simply, any operation that shifts the pixels around must be applied after deBayering. Furthermore, it is safest to crop after deBayering. The deBayering algorithms expect a certain color pixel in the first spot, and an even number of pixels--at least the algorithm with which I am familiar.

Cheers,
Alex W

[skeeloson@gmail.com]

Thank you Alex.  When I think like a pixel, it makes perfect sense.  Thanks again.  Scott