Dark Sky & Light Pollution - Learning Objectives

1. Why Dark Sky and Light Pollution
2. What are Dark Sky Lights?
3. How to support Dark Sky?

When we use carefully aimed, dimmer lights - instead of excessively bright, glaring ones - we can see better, maybe even see the stars.  Balance and restraint is the key to most things in life, and restraint also applies to lighting, especially in our night sky.
Visit my Dark Sky page at TOlighting.com

On the Hunt for Stars:
In Search of a Truly Dark Night Sky

How hard can it be to see the Milky Way? Read this article by Heather Smith and follow her journey to see the night sky. [1]  https://www.sierraclub.org/sierra/2018-2-march-april/feature/hunt-for-stars-dark-skies-preserves-and-parks

Visit Dark Sky Reserves to find places you can go to stargaze.

What is Dark Sky and why is it important?

How could the sky at night be anything other than dark? It seems like an easy question, until you look up and try to see the Milky Way in or near a large city.

If you want to see stars, you need a dark scene free from overhead lights and free from light pollution.

Light Pollution is the name for any light that is unwanted or uncontrolled showering wasted light into the sky. Reflected light from pavement and buildings is also contributing to light pollution.

Direct Glare from unshielded light sources reduces visibility in addition to requiring your eyes to adapt between bright and dark scenes, especially difficult for seniors and those with visual impairments. As we age the time it takes for our eyes to adapt from bright to dark, or dark to light, increases.; therefore, illumination without direct glare from seeing the light source is preferred.

2003 Northeast blackout affected 55 million people in the United States, many seeing the Milky Way for the first time.

For more see Astronomy and Dark Sky

Consider glare when selecting fixtures.

Before - Glare

After Shielded - No Glare

Did you notice the person at the gate? In the first photo, your eyes see the glare of the light, not the person in the view. The many types of shielded fixtures for your outdoor lighting are shown in the following chart. Your goal is to have the light pointed downward not toward anyone's eyes.

Dark Sky Friendly Lighting Retrofit

This Dark Sky Friendly image is from the December 2020 International Dark-Sky Association newsletter. It illustrates the growing interest and acceptance of the value of carefully planned lighting retrofits for towns and cities worldwide. The appeal of "warm-color, less-glare lighting" is demonstrated in the photo above.
"In Kozushima Village, under the strong leadership of the village mayor, more than 400 street and road lights were replaced with dark sky friendly fixtures in May and June of this year with the aim of being certified as a Dark Sky Park. The warm-color, less-glare lighting has changed the night scene in the village, creating a lighting environment that protects the natural environment and the night sky while ensuring the necessary brightness for the residents’ lives. Residents have well received the new lighting, and there are few safety concerns. The darkness of the night sky in the settlement area was significantly improved." [2]
www.darksky.org/kozushima-lighting-retrofit/
For more on Glare, visit my LED Glare page.

Dark Sky Lighting Fixtures
Luminaire Shielding Designs

This illustration shows the many types of outdoor lighting fixture designs that shield the light on the top and sides. This type of luminaire  is considered 'dark sky friendly.' to find a list of International DarkSky Association (IDA) approved fixtures visit their website. http://www.darksky.org/www.darksky.org/

How to support Dark Sky?

International Dark Sky Organization www.darksky.org
Find a chapter near you and learn more.

Become a citizen-scientists to measure & submit your night sky brightness observations.

https://www.globeatnight.org/   In 2017 citizen scientists from around the world contributed 15,382  data points.   Globe at Night is a program of the National Optical Astronomy Observatory, the national center for ground-based nighttime astronomy in the United States, operated by the Association of Universities for Research in Astronomy (AURA), under cooperative agreement with the National Science Foundation.
https://www.globeatnight.org/

Be sure to read the article about Davis LED Retrofit Zombie Lights, By James Benya

Bortle scale

Amateur astronomer John E. Bortle created the scale and published it in the February 2001 edition of Sky & Telescope magazine to help skywatchers evaluate the darkness of an observing site, and secondarily, to compare the darkness of observing sites. This scale is still used today to evaluate Dark Sky.

Bortle Dark-Sky Scale from 2001

Footnotes

1. Sierra Club https://www.sierraclub.org/sierra/2018-2-march-april/feature/hunt-for-stars-dark-skies-preserves-and-parks
2. Kozushima Village, Japan, Dark Sky Friendly Lighting
   

Photo Credit

• With Permission - ANCIENT BRISTLECONE FOREST | PHOTO BY HARUN MEHMEDINOVIC - to purchase his dark sky books and videos visit  https://skyglowproject.com/
• Before and After Glare photos by: George Fleenor/GeoGraphics Imaging
• Before and After in Kozushima Village, DarkSky.org​
• Luminaire Shielding Designs
  Image courtesy of Bob Crelin
• Bortle Scale, Wikipedia
  

Related Topics

Dark Sky Reserves, Dark Sky Ordinances,  Dark Sky & the Ecology of Night Lighting,   Astronomy & Dark Sky,  Circadian System, Glare