Dark Skies Initiative

McDonald Observatory is working with our neighbors locally, as well as groups across the country, to promote awareness of light pollution and simple solutions to it.

Dark skies videoDark skies video

What is light pollution?

Light pollution is any adverse effect of artificial light, including sky glow, glare, light trespass, decreased visibility at night, energy waste, and more. 

Watch a three-minute video on the causes and effects of light pollution, and discover ways to preserve dark skies.

Does it really matter?

YES! Light pollution wastes energy and money, disrupts global wildlife and ecological balance, has been linked to negative consequences in human health, and negatively affects astronomers and scientists. Read on to learn more about specific issues.

What can I do?

There is a WIN-WIN SOLUTION to light pollution! By changing outdoor lighting practices you can prevent light pollution while putting more light where you want it and using less electricity. Read on to find out how to make a positive difference.

Negative Effects of Light Pollution

A billboard exemplifying wasted light.A billboard exemplifying wasted light.• COSTS: In the United States $10s of billions annually in electricity costs are wasted shining lights upward at night. These numbers do not include the costs of harvesting fossil fuels to generate electricity.

• ENERGY CONSUMPTION: Most of the energy required to power all of the wasted light comes from burning fossil fuels, contributing to other types of pollution.

• HEALTH: New studies point to dramatic health consequences from the disruption of the natural human day/night cycle. Unnatural light at night affects hormone production and reduces the strength of the immune system.

• SAFETY: Vision is impaired by "glare" from overly bright light sources, reducing sensitivity to fine details and color perception, especially in elderly people. Brighter lights cause shadows to appear darker.

• THE ENVIRONMENT: Artificial light at night has been shown to disrupt the mating, migration, and hunting behaviors of many different species, and consequently the ecological community as a whole.

• LOSS OF NIGHTTIME SKY: The view of stars and dark night skies is rapidly being lost. Generations are growing up having never seen the Milky Way. Sky glow resulting from artificial lighting dramatically hinders the science of astronomy.

Light pollution: good, bad and ugly

 The Solution

We can reclaim vast amounts of energy currently wasted inadvertently into the night sky by poorly designed outdoor lighting. We can do this by using light fixtures that are shielded to reflect light down where it is needed, as well as using the smallest number of lights and lowest wattage bulbs necessary to effectively light an area.

The International Dark Sky Association has a list of distributors that sell approved fixtures to prevent light pollution.

• START WITH YOUR OWN HOME AND YARD: Lead by example in adopting good lighting practices. Put your own house in order first.

Good downward-pointing light fixturesGood downward-pointing light fixtures.• SPREAD THE WORD: The solution to light pollution is 90% education and public awareness, and 10% technology. Show examples of good lighting to your friends and neighbors. Once people see it in action, and understand its implications for cost savings and enhanced visibility, they are far more likely to adopt good lighting practices on their own.

• CREATE CHANGE IN YOUR LOCAL GOVERNMENT: One house doesn’t make much of a difference compared to an entire city and large retail complexes. The best way to make a significant difference is to help your local government create a new lighting ordinance that regulates lighting practices on a large scale. An excellent resource is the International Dark-sky Association.

Downloadable Light Pollution Flier suitable for printing (PDF, 460kB)

Resources and activities for teachers and educators can be found through the Dark Skies Rangers Program.

Additional Talking Points and Resources

Some of the information and wording on this website was taken from the International Dark-Sky Association.

Oilfield Lighting Can Coexist With Dark Skies (2 MB PDF)

The Strange Scourge of Light Pollution

StarDate Dark Skies Programs

June 28, 2010: Dark Skies
June 29, 2010: Little Constellations
June 30, 2010: Delphinus
July 1, 2010: Sneaky Stars
July 2, 2010: Moon and Jupiter
July 3, 2010: Sky Test
July 4, 2010: Deadly Skies

McDonald Observatory's Dark Skies Initiative is made possible in part through the generous support of Premack.com

NASA Satellite view of North America at night
NASA satellite view of North America at night.