Astronomers, billboard companies clash over signs that shine

PHOENIX (AP) — Arizona has long been a haven for astronomers who take advantage of its mountain peaks and vast stretches of dark, desert sky to gaze at stars and planets.

Astronomers and others use the corridor to observe the night sky for research, stargazing, GPS monitoring and even national defense purposes, said Jeffrey Hall, director of the Lowell Observatory in Flagstaff.

Phoenix billboards were exempt because the metro area already emits vast amounts of light, so a change would not make a difference for dark skies.

The proposal would allow electronic billboards along the Interstate 15 corridor in the northwest corner of the state that could impair a park with a dark sky designation, said John Barentine, program manager with the Dark-Sky Association.

Dark sky advocates are concerned light that the signs emit could affect the sensitive technologies used to look at distant celestial bodies.