Why is APP giving p...
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Why is APP giving purple stars when stacking from OSC?  


Brown Dwarf Customer
Joined: 3 years ago
Posts: 8
May 9, 2021 04:46  

I stacked 29X180 sec subs with darks, flats and dark flats in APP.   The smaller stars in the stacked image are purple.    I used the exact same data in DSS and the stars look normal.    What is the problem?

Camera is the 2600MC.   I also needed to force debayer on the subs.  I thought APP would recognize the data as color subs automatically?    The images below are with 15% stretch.


rho stacked in APP
rho stacked in DSS
This topic was modified 1 month ago by Tempus

White Dwarf Customer
Joined: 1 year ago
Posts: 11
May 21, 2021 06:46  

that's interesting.  i am having a similar problem with my unmodified dslr, canon 6d.  

Galaxy Admin
Joined: 3 years ago
Posts: 839
May 21, 2021 09:42  

@stephanhamel22 Hi Stephan. There are several factors that can influence the star colors. Can you tell us more about the data you're using, particularly the flats? How did you take them? What was the light source? Was any filter involved? As for the other images, are the gain, offset and temperature for all the same?

Regarding the automatic recognition of color data: if the application you use to shoot the images includes the Bayer pattern in the FITS header of the file then APP can detect that. Some application do not include the Bayer pattern in the FITS header and in that case APP needs to be told how to debayer the images.