A dark-sky preserve (DSP) is an area, usually surrounding a park or observatory, that restricts or reduces light pollution or maintains and protects naturally dark night skies. Different terms have been used to describe these areas as national organizations and governments have worked independently to create programs. DarkSky International (DarkSky) uses "International Dark Sky Reserve" (IDSR) and "International Dark Sky Park" (IDSP) among others when certifying Dark Sky Places.
History
DarkSky International was founded in 1988 to reserve public or private land for an outlook of nocturnal territories and starry night skies. Dark-sky preserves are specifically conserved for their cultural, scientific, natural, or educational value and public enjoyment.
In 2007, the Mont Mégantic Observatory in Quebec was the first site to be certified as an International Dark Sky Reserve by DarkSky. The same year, Natural Bridges National Monument in Utah became the first International Dark Sky Park. The Gabriela Mistral Dark Sky Sanctuary in the Elqui Valley of Chile was designated as the world's first International Dark Sky Sanctuary in 2015.
A dark-sky preserve, or dark-sky reserve, should be sufficiently dark to promote astronomy. The lighting protocol for a dark-sky preserve is based on the sensitivity of wildlife to artificial light at night.
Canada has established an extensive and stringent standard for dark-sky preserves, that addresses lighting within dark-sky preserves and influences from skyglow from urban areas in the region. This was based on the work of the Royal Astronomical Society of Canada.
Dark Sky Places DarkSky International's Dark Sky Places program currently offers five types of designations: International Dark Sky Communities – Communities are legally organized cities and towns that adopt quality outdoor lighting ordinances and undertake efforts to educate residents about the importance of dark skies. International Dark Sky Parks – Parks are publicly or privately owned spaces protected for natural conservation that implement good outdoor lighting and provide dark sky programs for visitors. International Dark Sky Reserves – Reserves consist of a dark "core" zone surrounded by a populated periphery where policy controls are enacted to protect the darkness of the core. These sites are established by a partnership of multiple land managers. International Dark Sky Sanctuaries – Sanctuaries are the most remote (and often darkest) places in the world whose conservation state is most fragile. The geographic isolation of these places significantly limits opportunities for outreach, so this designation is designed to increase awareness of these sites and promote their long-term conservation. Urban Night Sky Places – These places do not qualify for designation within any other category but are recognized for their efforts to educate the public on the benefits of proper outdoor lighting that ensures safety while minimizing potential harm to the natural nighttime environment. Urban Night Sky Places can be municipal parks, open spaces, or similar properties near or surrounded by an urban environment, but whose planning and design actively promote an authentic nighttime experience in the midst of significant artificial light. Dark Sky Developments of Distinction recognize subdivisions, master planned communities, and unincorporated neighborhoods and townships whose planning actively promotes a more natural night sky but does not qualify them for the International Dark Sky Community designation. This designation was retired in 2020.
Further designations include "Dark Sky Nation", given to the Kaibab Indian Reservation, and "Parashant International Night Sky Province-Window to the Cosmos", given to Grand Canyon-Parashant National Monument.
Dark sky preserves, reserves, and parks
As of January 2023, there are 201 certified Dark Sky Places globally: 38 Communities, 115 Parks, 20 Reserves, 16 Sanctuaries, 6 Developments of Distinction and 6 Urban Night Sky Places.