Diffraction spikes different color from stars' centers

[RupertTheBear]

Hi all,

I'm getting back into imaging after a long time away and am trying to relearn what I thought I knew.

I am disappointed in the RGB image below for various reasons. In particular, the diffraction patterns of the brightest stars are multicolored* - looks awful. I don't recall seeing this before or in other peoples' images. 

Has anybody seen this kind of thing before? Is it something obvious? Is there a wavelength dependence of spike to center intensity? Maybe I did something wrong in post processing. I can of course provide the raw data if you think they will help.

Scope: 8" Newtonian

Camera: ZWO ASI1600

Subs 30 s each, 2 hours each channel. I think the Bortle is 5 or 6.

Please let me know what you think and if I can provide any more details. Thanks!

 

*does the forum prefer "color" or "colour"? 

 

[wimvb]

Diffraction spikes are multi coloured because light of different wavelengths are diffracted to different positions. This is most notable in narrowband images. Have a close look at the brightest blue stars in this image

https://www.astrobin.com/full/6x98s9/0/