Dear Councilman Gates,
Arizona has some of the best astronomy sites in the U.S. Phoenix used to be one
of them until its rapid expansion causing a dramatic lost of our striking night
sky. I am a member of the Phoenix Astronomy Society, and I also host Astronomy
events with one of the largest telescope in town for educational purposes.
People that have attended those events keep coming back, but unfortunately, the
light pollution is becoming a serious nuisance for the entire Astronomy
community and for tourism. Studies have also shown that there is an impact on
health and security. Some lighting is less disrupting than other kinds, and a
thoughtful selection of our street lighting could bring back our wonderful sky
for professional astronomers, amateurs, and everyone else to enjoy. I have been
informed that you are planning to replace lighting with LEDs. Please consider
the Astronomy community’s needs while making your selection, like limiting the
bandwidth of the LEDs.
IDA Recommendations:
Always choose fully shielded fixtures that emit no light upward
Use “warm-white” or filtered LEDs (CCT < 3,000 K; S/P ratio < 1.2) to minimize
blue emission
Look for products with adaptive controls like dimmers, timers, and motion
sensors
Consider dimming or turning off the lights during overnight hours
Avoid the temptation to overlight because of the increased luminous efficiency
of LEDs
Only light the exact space and in the amount required for particular tasks
Please visit “The International Dark Sky Association” (IDSA) which has a
website with details about lighting problems and their recommended solutions.
For further details, please have a look at:
Policy Maker Info: http://darksky.org/lighting/policy-makers/ ;
<http://darksky.org/lighting/policy-makers/>
Guidelines:
http://darksky.org/lighting/led-practical-guide/ ;
<http://darksky.org/lighting/led-practical-guide/>
Thank you for your consideration,
Yves A. Klein
Estrella Observatory
4115 E. Via Estrella
Phoenix, AZ 85254
(480) 991 4470
