The terminology in question is "high/full cutoff": \* https://www.lrc.rpi.edu/pr... | Hacker News

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		throw0101a on Feb 4, 2022 \| parent \| context \| favorite \| on: New Zealand's bid to become a dark sky nation The terminology in question is "high/full cutoff": * https://www.lrc.rpi.edu/programs/nlpip/lightinganswers/light... * https://www.lrc.rpi.edu/programs/nlpip/lightinganswers/light... There are standards (RP-33-99, RP-2) from folks like: * https://en.wikipedia.org/wiki/Illuminating_Engineering_Socie... * https://energycodeace.com/site/custom/public/reference-ace-2... * https://www.shine.lighting/threads/122/ * https://www.denvergov.org/files/assets/public/doti/documents... IES TM15 11: * https://www.youtube.com/watch?v=EVPbuq4g5W4 * http://www.escolighting.com/PDFfiles/BUG_rating.pdf Generally you don't light to illuminate more that 60˚ from the nadir of the lamp: * https://en.wikipedia.org/wiki/Nadir

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