HomeMy WebLinkAbout2-9-2020 Public Comment - M. Baker - Street LightsFrom:Mark BakerTo:Cody Boyer; AgendaSubject:Moon vs. LED LightsDate:Sunday, February 9, 2020 8:56:16 PM
Dear Mr. Boyer,
Thank you for your article about the LED street lights.
http://secure-web.cisco.com/18z7064gDymKeZpAVsagSKk32rsVsBnAGy58P1os3FVJh1M7u3nhA03pEItpOoKEFpD2WMj0aut9RuRhdxcpipUGjxqvP2mjTM1bpz33_Uu9O-H788fnHzyK8eVRdapYaXa1W6_9blaFZgDhUozvTmCDJtNoNpXNRaircRCV3qeuPRQhWyFF4pxORD1EYsVl2tYUYbQpG5mvBOuUXM73XITtEfGYH6bavoxdi5JD8CEFpBBQ6G9-XsMkh5jWiApS6i1fyol5jjgRn6Lk8wTa9vQolvjDj_DuAsKwLIS1hnw-Tum8iC5b1Ic8rHR-Lidak1PELNfGYWf970iIJdmQAXg/http%3A%2F%2Fwww.nachhaltig-beleuchten.de%2Fblog%2Fen%2Fis-a-4000-kelvin-led-street-light-like-the-moon%2F
We are gravely concerned about the statement issued by Shawn Kohtz about how moonlight and LED lights ares similar:
“The LED lights look a lot brighter and, as it turns out, the LED light quality is very similar to the color of the moon, moonlight, and as you can
imagine, our eyes adapted to nighttime vision with moonlight so we can see much more effectively with LED light.”
This statement is incorrect and gives the public a false understanding of how light works. Moonlight is 4000 Kelvin CCT, but only .25 lux in brightness. With only moonlight, the conesin our eyes do not see the red wavelengths, so the light appears to have a blueish tint. But the color temperature of light that is most similar to moonlight's spectral distribution is 2200K.
Many engineers in many city cities have this misunderstanding of how light and the eye work, and thus many cities have made the grave error of installing 4000K and 5000K LED streetlights with a brightness of 75 lux at the street level. This type of light is dangerous for the eye, for human health, for emotional health and for the entire ecosystem which depends on thewaxing and waning of moon.
The following article provides easy-to-read information about how this works with sourcing from well-known experts in the field of night time light. http://secure-web.cisco.com/18z7064gDymKeZpAVsagSKk32rsVsBnAGy58P1os3FVJh1M7u3nhA03pEItpOoKEFpD2WMj0aut9RuRhdxcpipUGjxqvP2mjTM1bpz33_Uu9O-H788fnHzyK8eVRdapYaXa1W6_9blaFZgDhUozvTmCDJtNoNpXNRaircRCV3qeuPRQhWyFF4pxORD1EYsVl2tYUYbQpG5mvBOuUXM73XITtEfGYH6bavoxdi5JD8CEFpBBQ6G9-XsMkh5jWiApS6i1fyol5jjgRn6Lk8wTa9vQolvjDj_DuAsKwLIS1hnw-Tum8iC5b1Ic8rHR-Lidak1PELNfGYWf970iIJdmQAXg/http%3A%2F%2Fwww.nachhaltig-beleuchten.de%2Fblog%2Fen%2Fis-a-4000-kelvin-led-street-light-like-the-moon%2F
We are not attempting to place any blame on Mr. Kohtz or City of Bozeman, but without understanding how light and eye works, we will forever be installing the wrong outdoor lights.
I have copied that City of Bozeman on this letter in the hopes that they will install only 2200K, shielded and diffused lighting that makes use of timers or motion detectors to reduce theharm to our health and ecosystem.
Sincerely,
Mark BakerSoft Lightswww.softlights.org