Frequently Asked Questions:
- Light pollution—what is it and why is it important to know?
- What are examples of light pollution regulations, laws & policies?
- What are examples of effective lighting?
- What are some ways to measure sky brightness?
- What are some models of sky brightness measurements?
- What are some ways light pollution effects wildlife?
- What are some ways light pollution effects our health?
- What are some outreach programs that promote dark skies awareness and how can we get involved in them?
Light pollution—what is it and why is it important to know?
Light pollution is excessive and inappropriate artificial light. The four components of light pollution are often combined and may overlap:
- Urban Sky Glow—the brightening of the night sky over inhabited areas.
- Light Trespass—light falling where it is not intended, wanted, or needed.
- Glare—excessive brightness which causes visual discomfort. High levels of glare can decrease visibility.
- Clutter—bright, confusing, and excessive groupings of light sources, commonly found in over-lit urban areas. The proliferation of clutter contributes to urban sky glow, trespass, and glare.
For most of Earth’s history, our spectacular universe of stars and galaxies has been visible in the darkness of the night sky. From our earliest beginnings, the vast spectacle arrayed across the dark sky has inspired questions about our universe and our relation to it. The history of scientific discovery, art, literature, astronomy, navigation, exploration, philosophy, and even human curiosity itself would be diminished without our view of the stars. But today, the increasing number of people living on earth and the corresponding increase in inappropriate and unshielded outdoor lighting has resulted in light pollution—a brightening night sky that has obliterated the stars for much of the world’s population. Most people must travel far from home, away from the glow of artificial lighting, to experience the awe-inspiring expanse of the Milky Way as our ancestors once knew it. Read more about Light pollution.
What are examples of light pollution regulations, laws & policies?
- How I Beat Light Pollution in My Hometown
- France and fight against the Light Pollution
- Slovene Light Pollution Law
- Slovene Light Pollution Law—Press Release
What are examples of effective lighting?
What are some ways to measure sky brightness?
- Night Sky Brightness in Japan
- Measurements of Light Pollution in the Netherlands
Wim Schmidt is a member of the well-known dark skies awareness group in the Netherlands called Platform Lichthinder. Over four years he has made measurements of the night sky brightness using a digital camera and 2 Sky Quality Meters (SQM) made by Unihedron. The measurements were made for a few of the local Dutch governments. He has collected SQM measurements at 850 locations in the Netherlands and digital camera images at 1500 locations. All measurements were taken in the zenith with a clear sky and when there were no lights in the first 100 meters. A map of the SQM measurements is shown. Note that the higher the number, the darker the sky (less light pollution).
- Using a Digital SLR camera to monitor light pollution
- Sky Quality Meter monitoring of the night sky at the Zselic Landscape Protection Area
- Sky Brightness Nomogram
- Light Pollution in Hong Kong
What are some models of sky brightness measurements?
What are some ways light pollution affects wildlife?
- A Silent Cry for Dark Skies
- Deprived of darkness: the unnatural ecology of artificial light at night
What are some ways light pollution effects our health?
- Light at night and Breast cancer Risk Worldwide
- Preserving the Dark: Advocating Against Light Pollution at the American Medical Association
- From Science News: Darkness, Melatonin May Stall Breast and Prostate Cancers
What are some outreach programs that promote dark skies awareness and how can we get involved in them?
The Hellenic Astronomical Society joining the international effort of the IAU Cornerstone Project “Dark Skies Awareness” has dedicated a national action in dark sky and environmental education, informing the citizens and authorities, through a relevant leaflet and organizing a national photographic contest for students, amateur and professional photographers.
More information can be found on the Hellenic Astronomical Society website.
More outreach programs
- A Dark Skies Video Made by Chilean Students
- Promoting Dark-Skies and Astro-Tourism in Tanzania
- Reduce el impacto de la contaminación luminica - Fideicomiso de Conservación
- Lights at Night - from the Marion Koshland Science Museum of the National Academy of Sciences
- Light Pollution Trading Cards
- ”Light in Our Life” poster contest
- Dark Skies at Harkins Middle Video
- Mary Lou’s New Telescope
- Dark Skies in the UK
- Dark Sky Park Program in Hungary
- Thinking Worlds - an immersive 3D game about light pollution