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“As light pollution spreads, we are slowly losing one of the oldest

and most universal links to all human history.”

- Peter Lipscomb, Santa Fe Astronomer

Pittsburgh promises to become the first city in the eastern United States to become “dark sky” compliant in 2022. International Dark Sky week will occur the week of April 22 – 30, 2022. Massachusetts has a bill in the State House Senate to make one state park “dark sky” friendly. The Appalachian Mountain Club’s Maine Woods property became the first “dark-sky” park in New England in May 2021.

What is the “dark sky” movement? And, more importantly, what nexus does it have with land conservation?

At its core, the “dark sky” movement is a campaign to reduce light pollution. The movement began decades ago with professional and amateur astronomers who were alarmed that the nocturnal skyglow from urban areas was blotting out the sight of the stars. This resulted in the creation of the International Dark-Sky Association (“IDSA”,) a United States based non-profit incorporated in 1988 by professional and amateur astronomers. The mission of the IDA is “to preserve and protect the nighttime environment and our heritage of dark skies through environmentally responsible outdoor lighting.”

The benefits are not simply an enhanced sky vista at night. The movement seeks to reduce the myriad effects of lighting on the environment. For example, light pollution has been found to effect human circadian rhythms. Nocturnal animals are hurt because they’re biologically evolved to be dependent on an environment that provides a certain number of hours of uninterrupted day time, and night time. Light pollution has been shown to change food gathering and feeding habits, mating and reproductive behavior, migratory behavior, and social behavior. And, of course, reduced night time light usage also cuts down on energy usage.

The principles to implement this goal are best said by the Santa Fe Conservation Trust in it’s “Five Easy Ways to Bring Back the Stars:”

  • Ask yourself does it really need to be lit, and if so, does the light need to be on all the time?

  • Shield all exterior lighting

  • Light downward so the fixture does not permit light above a horizontal plane

  • Use motion sensors if you must light at night; and

  • Buy lighting according to lumen (light output) not wattage (power consumption.)


There is a connection between land and sky vista conservation. There are few if any places on earth that look the same as they did thousands of years ago, but when we look up at the night sky, we see a sky as seen by our ancestors. Light pollution is taking away those vistas as much as development takes away our land vistas. Conservation is not limited to land – there is protection for skies too. For example, the IDSA grants certifications to regions that have low to no light pollution. And, in a very proactive move, the Santa Fe Conservation Trust requires language to add the requirement of compliance with New Mexico’s Night Sky Protection Act in its conservation easement agreements.

Anecdotally, the State of Maryland has reached out to and is following the developments in Pittsburgh that opened this piece. For a deep dive on this subject, the LPT recommends the IDSA’s website

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