Light Pollution in Hawaii
by Richard Wainscoat
Light pollution is particularly obvious if you view Honolulu from a high
location, such as Tantalus.
Photo by Richard Wainscoat.
Next time you go out on a moonless, cloud-free night, take a moment to
count the stars. Chances are, if you do this in central Honolulu, you'll
be able to see 20 stars or less. If you do it in Hawaii Kai or Kailua,
perhaps you'll be able to see 200 stars. Only if you live far from
city lights, such as on the Big Island, will you be able to see the sky
in its full glory, with 2,000 or more stars visible to the naked eye.
The reason why we see so few stars in Honolulu is that city lights have
made the sky very bright. The brightening of the night sky by artificial
sources is commonly called light pollution. Sadly, much of the light pollution
across Hawaii (and most of Earth) is unnecessary, and is a result of poor
lighting fixtures and poor lighting design.
Many of our streetlights are poorly designed, and direct some of their
light directly up into space, where it is wasted. Athletic lighting is
particularly wasteful, with almost half of the light spilling onto adjacent
properties or lighting up the sky. Fully shielded light fixtures, which
direct their light downward only, dramatically reduce light pollution and
increase safety and visibility by reducing glare, which can be a particular
problem for older people.
Use of fully shielded lights reduces energy costs, because all the light
is directed where it is needed. California now uses only fully shielded
lights on its highways. The city of Calgary in Canada has just replaced
all of its streetlights with fully shielded fixtures that use lower wattage
lamps, yielding $2 million per year in energy savings. Hawaii wastes more
than $10 million per year in energy costs for poor lighting.
The night sky over the Big Island, where the Mauna Kea Observatories is
located, is protected by a strong lighting ordinance, which has preserved
the dark night sky over that island. The dark sky has now become a tourist
attraction, with the Visitor Information Station on Mauna Kea attracting
more than 100,000 visitors per year, many of whom participate in the evening
stargazing program. Many of Hawaii's visitors have never seen a dark
sky. Nevertheless, as the population of the Big Island grows, we must continue
to be vigilant to protect Mauna Kea's dark sky, and work to update
the Hawaii County lighting ordinance as necessary.
Maui County is now considering an ordinance to protect its night sky and
the sky over Haleakala. In the next state legislative session, the Institute
for Astronomy will again seek passage of legislation to improve lighting
at the airports and harbors on the Big Island and Maui (where the lights
are adversely affecting astronomy), and to improve the lighting on state
Good lighting is important everywhere, not just near observatories. Everyone
benefits from reduced road fatalities, better security, energy savings,
the ability to see the sky at night, the increased ability of endangered
birds and turtles to survive, and a better night's sleep.
Hear Richard Wainscoat speak online:
The International Dark-Sky Association: http://www.darksky.org