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The colour you see in the sky on cloudy nights is due to the reflection of city lights off the clouds. In rural areas, a cloudy night is, as you expected, significantly darker. However, the massive amount of light given off in urban areas reflects back to Earth when there is cloud cover. And so, you see a red-orange hue, similar to the overall colour ...


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This is really a very broad question; I will give you just a few pointers, but a full answer could fill a book. Yes, any 1D/2D pattern (barcode) scanner is looking at spatial variations in the received intensity; and it typically looks for "brighter/darker" to decide how to do the binary decoding ('1/0). Bar codes are constructed in such a way that they are ...


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From a physicist point of view it does not help! Pollution is the reflection of light in the atmosphere rather then lights around you. When you step underneath your chimney, you will still see all the reflection of the light in the atmosphere right above you. BUT: You will of course have a better view of the stars, as your eyes don't have to adjust to the ...


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Light pollution (as Chris White said in the comments) is less about glare from lights directly beaming into your eyes and more about the atmosphere itself being lit up and essentially drowning out the stars. The contrast between a light polluted sky and stars is too low for our eyes to make the stars out. One way to get around this is to use a filter. If ...



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