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Posted

interesting to me how the sky above the Parthenon, when the building is lit up, is very dark. But when the lights go out, suddenly the sky becomes fairly bright...?

Posted

interesting to me how the sky above the Parthenon, when the building is lit up, is very dark. But when the lights go out, suddenly the sky becomes fairly bright...?

I noticed that too, and not just in that pic, but also in others, like the Moscow State University one, or the Forbidden City one...

I'm no professional, but I guess it has to do with the contrast, with the BIG light source gone you suddenly can notice the more ambient lights in the background...

...or so :P

Posted

It is a function of exposure time combined with hazy or overcast skies. When the bright building lights are on, an exposure of perhaps a half second is all that is necessary for a detailed image. That relatively short exposure does not give the night sky with reflective overcast a chance to record its dimly lit presence. With the bright building lights turned off, an exposure of about 15 or so seconds is required to ensure detail, which also makes the overcast clouds glow with the surrounding city lights. You will notice that in certain pictures, when the sky is cloudless, there is no change in the darkness of the night sky between the two exposures, since there are no clouds off of which the city lights may reflect.

Posted

which also makes the overcast clouds glow with the surrounding city lights.

but.... this was Earth Hour. No lights were supposed to be on anywhere. ;)

Thanks for the 'splanation, Ron. I feel superiorly knowledgeable. :grin:

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