Sky & Telescope - January 2024 - 28

Light Pollution: Policy
Each year, outdoor
lighting in the U.S.
consumes
380 terrawatt hours
- enough to power
35 million homes
SOURCE: U.S. DEPARTMENT OF
ENERGY 2016 / DARKSKY
INTERNATIONAL
1%
Fraction of outdoor lighting
that serves a useful purpose
SOURCE: U.S. DEPARTMENT
OF ENERGY 2022 / DARKSKY
INTERNATIONAL
Fraction above natural
<0.01
0.01 - 0.08
0.08 - 0.32
0.32 - 0.64
0.64 - 1.28
London in 1948, relocating to the grounds of Herstmonceux
Castle in east Sussex. And in 1958 the city council of Flagstaff,
Arizona, enacted what may be the world's first outdoor
lighting law, intending to reduce the impact of lighting on
astronomy.
Attention has since spread to a global level. Thirty-five
years ago, two astronomers - one professional, one amateur
- founded the International Dark-Sky Association, which
recently rebranded itself as DarkSky International. From
the outset, the organization intended to confront what was
already an obviously global problem, not one limited to more
technologically advanced countries. Some people began considering
a " right to starlight " that international treaties might
one day recognize. In 2007, a non-binding resolution sponsored
in part by the United Nations Educational, Scientific
and Cultural Organization (UNESCO) and the International
Astronomical Union (IAU) declared that " an unpolluted night
sky that allows the enjoyment and contemplation of the firmament
should be considered an inalienable right equivalent
to all other socio-cultural and environmental rights. "
28 JANUARY 2024 * SKY & TELESCOPE
NIGHT-SKY BRIGHTNESS Based on both satellite data and groundbased
measurements, this map shows the artificial brightness of the
night sky as a ratio to the natural sky brightness. Blue areas qualify as
polluted by astronomers' standards. People in yellow areas cannot see
the Milky Way in January; in orange areas, June's brighter Milky Way
also disappears. In red areas, there is no true night - an artificial twilight
reigns, blotting out the stars.
Where We Are Now
Astronomers began studying light pollution systematically
in the 1970s, around the time the city of Tucson, Arizona,
introduced the first comprehensive policy regulating outdoor
lighting in the U.S. As computing power increased in the
1980s, the first sophisticated models of skyglow became available.
Today, our most complete and up-to-date view of the
issue comes from a combination of satellite remote-sensing
observations of Earth at night and the efforts of thousands
of citizen-scientists around the world who have contributed
observations to the Globe at Night program.
Satellite observations tell us that on average during the
early 2010s, the land area of our planet showing indicaF.
FALCHI, P. CINZANO, D. DURISCOE, C. C. M. KYBA, C. D. ELVIDGE,
K. BAUGH, B. A. PORTNOV, N. A. RYBNIKOVA, AND R. FURGONI

Sky & Telescope - January 2024

Table of Contents for the Digital Edition of Sky & Telescope - January 2024

Contents
Sky & Telescope - January 2024 - Cover1
Sky & Telescope - January 2024 - Cover2
Sky & Telescope - January 2024 - 1
Sky & Telescope - January 2024 - Contents
Sky & Telescope - January 2024 - 3
Sky & Telescope - January 2024 - 4
Sky & Telescope - January 2024 - 5
Sky & Telescope - January 2024 - 6
Sky & Telescope - January 2024 - 7
Sky & Telescope - January 2024 - 8
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Sky & Telescope - January 2024 - Cover3
Sky & Telescope - January 2024 - Cover4
Sky & Telescope - January 2024 - SA1
Sky & Telescope - January 2024 - SA2
Sky & Telescope - January 2024 - SA3
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Sky & Telescope - January 2024 - SA8
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