Who has naked eye Milky Way?

[Keiran]

Almost alway at my dark sky site. But at home, not a chance.... I struggle to see stars

[EasyFlier]

Milky way, lots in the kitchen, kids love them!!

[pete_l]

Interesting, such thing are RELATED - Even if evidence doesn't always tally! <G>. An internet search on sky-meters and sundry formulae is interesting tho'? Background (sic!) to my VIDEO astronomy, and all...

Yes, I think there are a couple of factors.

First, my eyes. I wear varifocals so hitting the sweet spot - viewing through the part of the lens that is focussed on infinity is not easy. Visual accuity varies with darkness - so a spectacles presciption that works in daytime tends to be a little "off" in full darkness. So I'm probably defocused a bit

The other issue is the nature of the light pollution. The LP/magnitude models make the assumption that the viewer is in a perfectly dark location and that the only light they see is in the direction of the sky. So the image they receive is made up of light from stars/objects AND back-scattered polluting light from faraway sources. When the intensity of back-scattered light exceeds that of the object you're trying to see it becomes more-or-less masked in LP.

I think that model doesn't account for light pollution at ground level that shines directly at your eyes and doesn't come from back-scattering. That light such as from streetlights/security lights or lit rooms (without curtains) is bright enough to prevent your eyes getting fully dark-adapted. Without full D-A eyes aren't sensitive enough to see dim sources that are at the level of the theoretical limit of back-scattered light - as measured by an SQM.

As a consequence I reckon I would be able to see down to a VLM of 5+ at the zenith as my SQM indicates I should, provided there weren't any direct sources of light in my field of view. I'm not prepared to wander round with a large black tube over my head to keep stray light out - the neighbours already think I'm crazy. I don't need to confirm their suspicions

I know that when I am at my dark site, somewhere in the mid 21's MPAS (it varies; there's never any such thing as an absolute or constant darkness for any site, anywhere) depending on the season/solar cycle/humidity/time then I can see close to the calculated limit of 6.3