[AZ-Observing] Re: City of Phoenix will use 2700 Kelvin LED streetlights
- From: "Tom Polakis" <tpolakis@xxxxxxx>
- To: <az-observing@xxxxxxxxxxxxx>
- Date: Fri, 2 Dec 2016 20:50:21 -0700
Good news, Folks!
I just heard on the radio that the City of Phoenix is going to use 2700 Kelvin
LED streetlights instead of the 4000 Kelvin LED lights approved in the
original
contract.
The squeaky wheel gets the grease!
This is good news if we have to live with the LED's shining in our faces,
yards
and telescopes.
A hard copy of this announcement should be coming out real soon.
This decision is good for us, but it may not have as much of a benefit for
visual observers as it will for professionals. This paper in "LEDs" magazine,
whose existence I only learned about minutes ago, indicates that the real
problem with 4000K lighting is the much higher peak illumination around 450 nm.
Even after accounting for increased scattering of bluer light, the
across-the-spectrum illumination is not significantly less with the warmer
2700K lights.
http://www.ledsmagazine.com/articles/print/volume-12/issue-10/features/street-lights/light-pollution-depends-on-the-light-source-cct.html
Other cities that already use LED streetlights are changing to lower color
temperatures as a result of complaints unrelated to astronomy. Apparently,
folks don't like streets to be lit up like prisons.
Tom
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