[SQM] [walnutpointobservatory] Re: a "ground albedo influence" night
jpmayer at ameritech.net
Mon Dec 21 03:30:52 UTC 2009
Jan Hollan !!
Hi, Jan. I'm Joe Mayer, the observatory director of the Chicago Astronomical Society and I've investigated this problem with an illumination engineer from Portland, Oregon. I can't put my hands on the papers right now; nor can I remember the engineer's name. However, he is a former board member of the IDA.
His calculations and measurements produced the following results: Given a fully shielded illumination source such as a street light, from a dry asphalt surface, 8% of the incident light is reflected into the atmosphere. From a dry concrete surface 25% of the incident light is reflected into the atmosphere. From a wet surface it's no problem: It's raining.
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