Shame you missed it. I wish I had been having a few bears, maybe then I could have explained it. I've been thinking about it all week trying to come up with some ideas.
I've found a couple of references. These are from Jerry Lodriguss' site
"The dark night sky is illuminated by a natural skyglow that is composed of four parts.
Airglow is the brightest component and is caused by oxygen atoms glowing in the upper atmosphere which are excited by solar ultraviolet radiation. Airglow gets worse at solar maximum. Airglow can add a faint green or red color to the sky background. The color may be vivid if there is a strong aurora occuring."
"Is the color of the faint natural airglow green?
Yes. Usually you see the 5577A line emission as green as seen in the Gordon Garradd photos mentioned above.
What color are the Gegenschein and Zodiacal light?
They are simply scattered Sunlight, so they are exactly the color of the Sun. (The Zodical Light dust particles are "big" so they don't scatter blue preferentially, unlike the small particles of air, which are roughly the same size as the wavelength of light.)
I've been able to convince myself that the very brightest part of the zodiacal light near the horizon, probably close to the time of astronomical twilight, is right at the threshold of color for me and is a funny turquoise blue-green, i.e. right at the peak dark-adapted color.
If you've ever looked at a discharge tube of oxygen with a simple cheapo replica grating and seen that gorgeous line at 5007A, that's the color, but barely perceived. Chris Schur told me once he sees the color very strongly, but for me it's a marginal thing."
Though it wasn't the Zodical light because it was so even. As I said it was very eerie and bizzare