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That “good light” is only all good if you paint the ground with vantablack, otherwise a decent amount if it still bounces back up. So you want to aim all the li
by wlesieutre 6y ago
That “good light” is only all good if you paint the ground with vantablack, otherwise a decent amount if it still bounces back up. So you want to aim all the light downwards, yes, but it’s also important not use more light than necessary.
- DoingIsLearning 6y ago> So you want to aim all the light downwards, yes, but it’s also important not use more light than necessary. Note that the little diagram also dims the light source from 500W to 100W. :) In terms of candela, sure some light will always be reflected upwards but focusing on that really is a case of the perfect is the enemy of the good.
- wlesieutre 6y agoGood point, but I read that as being more that 400W were going into the neighbor's window or up into the sky, and the 100W is intended to keep same light levels as before. If you don't need those light levels, a 50W floodlight would cut the remaining light pollution from upward reflections in half.
- ben_w 6y agoIt can make a massive difference. I grew up in village near Portsmouth (UK, metro area population 1.5 million according to Wikipedia), and the night sky was bright orange whenever it was cloudy. I now live in Berlin (6.1 million metro population), and although it isn’t perfect darkness, it is vastly better even though I’m in a built-up part of the city rather than a rural part of the city equivalent to my childhood area in the UK.