[Ryderscope (Rodney)]

Thanks for raising this issue Peter, it's a great topic to explore. I don't have an exhaustive response as yet but can raise a couple of quick points and questions.

"I'm posting this question here because ultimately it involves equipment choices."

I am wondering what equipment choices would be reliant on a specific approach to colour management?

As for the arguments in the Clarkvision article:

Roger Clark's article is very detailed and is very informative on the science behind understanding colours in space and specifically in the Milky Way as they are applied to different chemical elements and dusty regions. However, I think that there is a gap between an attempt to codify what is "correct" colour management by referring to the science of colour and the reality of how we perceive colours as human beings. Aesthetically when we some colour groupings side by side they either look or they don't. Looking at the widefield Orion image in the article, the colours in this image may be correct according the Mr. Clark's 'natural' colours but you would not see too many versions of this field using the same colour balance.

The problem is that there is no agreed authority and what is correct colour and what isn't in an astrophotograph. I've seen, for example, images commented on in competitions as the colour not being quite right but with a lack of follow up to say what exactly that means and what the colour should have been or should not have been.


Edit: Thinking further about this, I wouldn’t want to give up the detail that pops out in Ha. Why not collect red data with a filter that more matches what our eyes might see if they were simply more responsive. That would give a good colour balance. Then blend in Ha to luminance for the detail? I suppose we do that anyway in RGB imaging but perhaps with too much red.

Exactly, we are making the image do what we want it to do. We want to see lots of detail of what is there and a great way to do this is to add colour to it. For what it is worth, I have recently started to do what you describe in mixing the Ha with the Luminance to use as the Luminance channel so that it carries more detail.

And finally, the Clarkvision article discusses the emission lines in different ionised Hydrogen and the scattering of light by minute dust particles in the Milky Way. There is, however, no mention of star colours which is another rabbit hole that we could go down. Whist there is a well defined system for classifying stars based on the colour (temperature), there remains a lot of subjective control that can be applied in post processing when it comes to enhancing the star colours.

Clear skies,
Rodney