[AJames]

I have been reading the descriptions about the colour of the Orion Nebula here with some interest.
Attached is an image of the Orion Nebula, which to my eyes seems about colour that I see. The difficulty for the image here, however, is also showing the true luminosity of the gas, which in the telescope seems more lightly pearly white or "grey" than any kind of green.
Those wishing to see the "grade" of the colour might find it best to try and put the nebula and stars slightly out of focus. This will makes the green colour more washed out near the edges of the nebula, while the light around the central trapezium is a much lighter green or whiter or "greyness."

Note: I have an article on the history of the "Orion Nebula" on my website, which was only recently updated, and this might be of interest to the curious on this grand nebula of the sky. http://homepage.mac.com/andjames/Page204.htm

As to the Tarantula Nebula or even Eta Carinae, I also see not visual colours - the latter (Eta Car) appears merely as pearly white, which I think is just because the light spread over a much wider area.

Regards,
Andrew

IMPORTANT NOTE : "Grey" is an impossible in stellar objects or nebula, as all have light that is chromatic - composed of multiple saturated colours as we seen in spectra or as hues. There is no black or white (grey) scale with any such objects. Ie. The heavens are not like black and white photography.
So-called “acromatic colours” in painting and art are regarded as achromatic or neutral, but whether white or black are colours is open to debate. White light is in reality is NOT defined as a colour because it compromises the sum of all the radiations of the perceived visible spectrum. With light there are no mixtures of black and white in starlight or sunlight, so what we are really describing is a montage of monochromatic hues.
This is far different from the artistic view of colours in the world. What the eye visually sees cannot be adequately described in these terms - a fault with the persistence of the early ideas of colour. (It is also a failure of certain untenable colour descriptors often wrongly used by observers.)

There is absolutely no need, therefore, to describe colour in terms of tone, value or purity OR even for “lightness” (grayness). There is only hue and saturation in starlight and sunlight.

“Greyness” is decribed in and white photography as chiaroscuro (white-black-grey). The term is also used in the describing the treatment of light and shade in pencil or charcoal drawings and painting. This Italian word comes two words chiaro - bright and clear and oscuro meaning obscure and dark. (In Latin, clarus & obscurus, also an Italian oxymoron!)