Ian Ashdown, P. Eng., FIES, Senior Software Engineer for Lighting Analysts Inc., wrote an interesting whitepaper, Classifying Outdoor Luminaires: The Limits of BUG, available for free download here. The abstract: “The IES BUG rating system is useful for classifying outdoor luminaires when considering light trespass, sky glow, and glare in accordance with the Joint IDA-IES [...]