Chicago area home to the world’s largest Urban Night Sky Place
This past August, Chicago area residents gained the bragging rights to the world’s largest Urban Night Sky Place (UNSP). Over 6,600 acres of the Forest Preserves of Cook County’s Palos Preserves received the designation from the International Dark-Sky Association (IDA). The area is a living jewel protecting the world of night as it was meant to be with virtually no artificial light in sight.
The IDA’s International Dark Sky Places program was founded in 2001 to encourage communities, parks and protected areas around the world to preserve and protect dark sites through responsible lighting policies and public education. There are nearly 200 Dark Sky Places across the world. The Urban Night Sky Place designation is a relatively new effort. It was initiated in 2018 to recognize locations close to - or even within - urban areas that protect the nighttime environment through thoughtful light pollution-friendly lighting, experiences and educational outreach about the importance of dark nights for all living things.
“For the entire history of life on Earth, dark nights followed sunlit days. In a little more than a century we’ve altered that natural pattern by illuminating our nights. Living in and around Chicago we’ve grown accustomed to always having bright lights in view. The chance of experiencing a natural, dark night—as it was for eons—is now too rare. It’s difficult to express the peaceful, natural beauty one can experience within the Palos Preserves’ pristine nights. This designation is a recognition of the value it offers to everyone in the region,” said Ken Walczak, Senior Manager for Far Horizons at the Adler Planetarium.
Dusk from McMahon Woods. The only lights in sight are those of a celestial nature.
About four times more stars are visible at the Palos UNSP than in the City of Chicago as measured by students from the Adler Planetarium, which partnered with the Forest Preserves to submit the application. Sure, you’re not going to see the Milky Way stretching from horizon to horizon but you will discover nighttime vistas unblemished by artificial light.
“People know the Palos Preserves for its extensive trail system and the natural wonder of the hills, bluffs, woodlands and wetlands. I’m pleased that with this Urban Night Sky designation, the site is also recognized as a location that preserves the night. The many species of plants, insects, birds and other animals that call the Palos Preserves home benefit from the absence of disturbing artificial lighting,” said Arnold Randall, the general superintendent of the Forest Preserves.
Receiving this IDA designation involved a rigorous application process which took two years to complete. To measure and document the light levels in Palos Preserves, the Adler Planetarium worked with teens in its Far Horizons Stratonaut and Summer Internship programs to use specially designed cameras, built by students and volunteers at the Adler to measure the nighttime sky in the area. The students also used satellite data and images from astronauts on board the International Space Station for the application. The Adler also provided guidance in a light management plan that was initiated by the Forest Preserves, which reduced light levels at the Preserves’ buildings with a combination of timers, shielded fixtures and night sky friendly LED lighting. The application also required a demonstration of robust community support for dark-sky protection, a commitment to stewardship of the nighttime environment and nighttime education programs.
Palos Preserves (outlined) in a 2016 ISS image is only 25 miles from downtown Chicago yet has almost no visible lights (except for LaGrange Road which cuts through the preserve). Image Courtesy of: Earth Science and Remote Sensing Unit, NASA Johnson Space Center
“The Forest Preserves’ commitment to understanding the principles of responsible outdoor lighting, engaging in community outreach, and providing access to this natural resource for the residents of the Chicago area all serve as commendable examples of what UNSPs can offer,” stated Ruskin Hartley, Executive Director of IDA.
Forest Preserves sites are closed at sunset so, for now, visitors who want to enjoy the night at this Urban Night Sky Place can keep an eye out for the Preserves’ guided nighttime programming in Palos Preserves. Plans are being developed to offer nighttime permits to groups and organizations for future stargazing and night environment events. The Forest Preserves and Adler Planetarium will continue to partner in the Palos Preserves for fun and educational programs and events like stargazing nights, night hikes, owling and light pollution awareness programs.
