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I use an ASI294MM Pro with ZWO RGB filters and a ASI294MC Pro unfiltered. Every time I process an image with either camera and do a star color calibration the blue stars look like every other image I search for that target but the stars that should look yellow judging by other images always end up red/pinkish. I process the MC unfiltered with default settings, remove light pollution and then a star color calibration. With the MM I process with default settings, remove light pollution from each frame and then normalize. I then combine RGB with RGB-1 algorithm default settings and then remove light pollution from that result and do a star color correction. The results from both cameras have the same colors, but they do not match what I see when looking up the same target taken by other people. What am I doing wrong?
Could you post a few examples of the effect you're seeing? Also, are you combining the RGB with the MM data or really just both separate?
@vincent-mod I have not combined any images from the cameras, but will probably try in the future. I have the MC on a 300 focal length and the MM on a 2,074 focal length. I will upload some images when I get home this evening.
After Combine RGB
After star color calibration
I see and how do the star color calibration plots look like? It may be that you have to adjust the correction a little bit. Also, after this the HSL selective color tool can be used to adjust the red a little as well.
Hi,
I do not know what colour balance you were looking for but assuming that you are also shooting LRGB, your results do not look too dissimilar to my outcomes when targeting globular clusters (but that is not to say that my results are actually chromatically correct).
M13
M94
I use Adobe Camera RAW to tweak my APP results as I find this is easier to use than APP HSL.
I have looked at many images of clusters on Astrobin and many show a preponderance of Blue stars but generally these seem to be NB images.
Based on this analysis of Hubbe imagery I think LRGB globular cluster images should show star populations tending towards yellow / red (which I think endorses APPs Adaptive Black Body method).
https://www.e-education.psu.edu/astro801/content/l7_p5.html
Hoping for an interesting discussion.
Mike
Always an interesting discussion indeed. 🙂 In the end, it's always up to what someone wants. The APP black body model is a very nice method to get accurate results, mostly when not using filters and definitely being pure broadband data. When using filters, you may have to change the slopes etc to match the star population and tweak it a bit.
I did not post the pics, but I have my scopes side saddled and captured ASI294MC Pro data at the same time on the wide field setup. The OSC unfiltered image resulted in the same exact star colors which were blues and reds. I have since found a few pics on google with red stars in M5, but the majority are blue and yellow. I too use camera raw for color adjustment as I am used to it.
If I adjust the stars to look more like the colors from the majority of internet pics then the slopes are not even touching the stars which just seemed wrong to me. I just want to have stars as close to realistic colors as possible, but even hubble footage can vary greatly in coloring so it is hard to find a good benchmark.
