Why is the sky not dark even on "dark" nights?

[Linda]

We discussed this recently in another topic. It does indeed quite light under a sky with clear milkyway visible.

If you want to know whether you have a dark sky, then just look at the amount of stars you see. If they are uncountable, you're under very dark skies.

[Tony72]

As a newbie I found this thread interesting

Tony72

[nytecam]

Thank your-lucky-stars if you have the dark skies [with a hint of airglow!] described by most posters here.  Here is SW London dusk just freezes and gets no darker and replaced by an overall orange glow - even finding Polaris can be a struggle and may need averted vision! 

I don't worry as I've not used an EP for ages on DSOs and rely on my camera in very brief exposures viewed in essentially realtime to cut through the muck with impunity. Even the Hubble Deepfield is possible near the zenith or maybe TNO Eris @ m 18.5 below the celestial equator via my setup ;o)

Nytecam