[PRejto (Peter)]

Hi Rodney,

Thanks for your detailed and thoughtful reply! You make a number of great observations.

Well, yes, colour is pretty subjective. We cannot even agree that humans "see" the same thing at all from person to person, but we assume that we do and I think it is a reasonable leap as a starting point.

Here is my attempt to put this in perspective. Suppose I told you that I have a great new blue filter that captures amazing UV and that your images will now look so rich in blue. Would you accept that? Probably not, so I see no difference with the red filter. Our eyes don't have great sensitivity to Ha but the cameras sure do and the filters just transmit it all...and it overwhelms the red signal. So, why not use a filter (equipment!) that transmits the proportion of light that our eyes naturally respond to? Every normal digital camera sold for everyday use does this, but we insist on removing that filter so these cameras can see more Ha...and the white balance goes kaput. Images with this everyday white balance would not be devoid of red...in fact, t seems that other colours and shading would emerge,,,oranges, browns, etc that currently are all just red.

Now, lets not confuse stretching and detail with colour. There is much that is artificial and manufactured in our images. My question only concerns whether we as astrophotographers are deluding ourselves into thinking that RGB imaging is presenting "true" colours. i.e., "if only our eyes were more sensitive to the coloured light, this is what we will would if the light is boosted enough to perceive it." To beat a dead horse, if I took a picture of grass at night with an astro-camera and processed it normally and then said, this is what grass looks like if only there was more light we would laugh. But, we do exactly that every day with objects in the sky. This is why I want to experiment more with a red filter that more matches the human eye's response. I have no problem collecting Ha and adding to luminance and creating a totally artificial picture. Or, maybe I should just give up this quest all together and say it's all artificial and in the end "art" and be done with it.