[Darksheare]

You do realize that the camera there operates on emitted/reflected light, not size of the object?
And comets have a nasty habit of outgassing, which reflects light.
And not at all in correlation to size of the comet?

[MD Expat in PA]

You do realize that the camera there operates on emitted/reflected light, not size of the object? And comets have a nasty habit of outgassing, which reflects light. And not at all in correlation to size of the comet?

Actually contrary to what was posted regarding the STEREO-A image, ISON was actually closer to the camera than Eneke and by a very large factor. (See my previous post and links.)

Comet Eneke while larger than ISON, is a periodic comet that completes an orbit of the Sun once every three years — the shortest period of any known comet. Unlike ISON which was making its first trip into the inner solar system and is (was) a close sun grazer, and rather unsuccessfully since it broke up and disintegrated, Eneke is not a close sun grazer but its regular orbit through our solar system and around the sun has what astronomers call “hardened” it, i.e. its regular orbit of once every three years has created a tough outer shell and hence a rather small coma. Eneke also has a very low albedo, reflecting only 4.6% of the light it receives.

ISON on the other hand, while its nucleolus was smaller than Eneke, being “a comsic virgin”, it had a larger coma on its inbound path because it had a lot more icy material to outgass.

[Yosemitest]

Like I said before:

"Remember, Comet Ison's nucleus and Comet Eneke's nucleus had just had their giant comas torn away from them by a Solar flare."

I know they operate on reflected light.
But there's more there, relative to size, than you're willing to admit.