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...Any argument to the contrary is simply false.

....So stating that "If a nebula is under cones threshold it will never get above whatever the size of the scope" is inadequate to explain what I have seen. If the cones are active enough to see color in larger apertures, then I should see it in smaller apertures is the implication, yet this simply is false and verifiably so.

...The physico/psychological reason for it is, IMO, poorly explained in the literature, and I have read extensively on the subject. Clark's articles attempt to bring it to a mathematical explanation, but I am left unpersuaded. I SEE an improvement in brightness and contrast and color in larger scopes. Arguing that it doesn't happen gets nowhere.

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I think you definitely should read the two papers. They explains what you and other people see, and why not al people see the same. I understand that some people may dislike the conlusions, but I think they are solid.
One example is that you see geeen the brightest part of M27 (which in fact is red, and reddish the fainter part, which in fact is greenish). Studies show that when vision is mediated only by rods colours are related to the context: brightest lights are greenish and middle lights are reddish. This exactly fits your experience and explain why you see green the red part of M27 and red the green part (I understant the disappointement, we all tendo to "believe" to our eyes).
When I mean scientific studies I mean works published on scientific journals *after peer review*. When I mean "literature" I mean that.

As for what concerns the size of the scope I think there is a little confusion. One object that is below the threshold of cone detection cannot be seen in color. However being above the threshold is a condition necessary, but not suffcient. You also need a given size for the colour patch to be recognized. That is why the experiments have been carried out with samples that were seen under an apparent angle of 8°. A smaller patch is more difficult do be recognised either as shape and, as colour. Here is where a bigger scope helps: it provides bigger images where colour can be recognised, but only if the brightness is above the cones' threshold.

In other words: if a nebula is below cone thresholds you will never see it in colors, If it is above, you need another condition: a telescope that provide a image large enough to be recognized. This is the concept you mean and which is explained by the "optimal magnification" by Clark. However in the case of colors you have also to consider that as you push magnfication the surface brightness decrease. This may not be aproblem for shape recognition (as long as the surface brightness is within the reach of rods) but may be a problem for cones, because they reach is far shorter. So in an attempt to magnfy the image to improve its perception, you may end in lowering the surface brigthtness below the thresholds.

Edited by Mauro Da Lio (11/25/07 12:02 PM)

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