protoindoeuropean:

posttexasstressdisorder:

It would be nice to be able to actually see the night sky again.

light pollution is horrible, idk who designed this graphic though, because the difference between “bad” and “better” is marginal (because the displayed effect of the lighting is not correct) and the only kind of lighting up there that is ok at all is the one labeled “best”

the light scattering of the “best” kind of lighting is actually like the bottom kind in this picture:

showing both the directed light of the light source and the scattered light of the flat lamp surface (if you stood where the human is pictured, you could see the light bulb(s), but if you stood outside of the inner cone, even if relatively far away, though you couldn’t see the light bulb(s), you could still see the illuminated glass or plastic surface of the lamp, which causes its own light scattering; both need to be kept under the horizontal line to minimize light pollution)

of course any kind of lighting with convex lamp surface (which is also not shielded obviously) will cause scattering of light above the horizontal line

and though not marked so in the graphic below, even fully shielded lamps with flat surfaces will cause scattering above the horizontal line if positioned at an angle (again, only directed light is displayed below, ignoring the scattered light that goes above the horizontal line)

(b) is obviously still better than either © or (d) and even than the “better” kind of convex lighting in the original post, but still not optimal and only (a) is actually good

when it comes to light pollution, after all, the most far-reaching effects are caused by light emitted at angles closer to the horizontal line: a light ray travelling perpendicularly straight up into sky will pass through a couple ten km of atmosphere then leave the earth. on the other hand, a light ray emitted at a 5° angle (for example) will travel through a couple hundred km before exiting the atmosphere