We all know sea turtles dig the dark at our beaches. Light pollution distorts the natural ambient light pattern and confuses new-born hatchlings that need a dark, starry night sky to orient themselves toward the ocean.
As for the human species, stargazers have been headed to the Central Idaho Dark Sky Reserve, one of the best dark sky destinations in the world. It's an area spanning 1,416 square miles stretching from Sun Valley/Ketchum through the craggy Sawtooth mountain range up to the tiny mountain town of Stanley.
Last year the International Dark-Sky Association (IDSA) announced the Reserve accreditation, marking the first of its kind in the United States. The super-strict designation applies to just a dozen places in the world, including remote regions in New Zealand, Germany, Wales, and Namibia in southern Africa, where the skies are so "exceptionally dark" the light pollution is nearly zero. The isolated locations must have a firm plan in place for long-term conservation.
In the Central Idaho Reserve shooting stars, meteors and comet sightings are the norm. So is the purple cloud of the Milky Way-- that torrent of stars which slashes across a deeply darkened sky in the southwest quadrant each night. Recognized for the quality and depth of the darkness, astro-photography opportunities are as plentiful as anywhere in the country.
The authoritative voice on light pollution, the IDSA nominates each destination based on its level of darkness. To qualify, each reserve must also meet or exceed a night-sky brightness of 21.5 MPSA (magnitudes per square arc second), the official unit used to measure the luminosity of the night sky.
An intensive effort by volunteers taking darkness readings throughout the region combined with a new generation of satellite measurements spurred the IDSA decision. Dark sky measurements can be easily done with a small digital device that looks like a pager or even a smart phone utilizing the Dark Sky Meter App or the Loss of the Night App as recommended by IDSA.
My wife Jane and I travelled from Sun Valley up Highway 75 sixty miles north into the heart of the Sawtooth National Recreational Area. More than 40 jagged 10,000-foot granite peaks provide a majestic background for leg-burning hiking and mountain bike rides, a horseback ride climbing steep switchbacks above a gorgeous mountain lake, or novice fly-fishing standing thigh deep in rushing streams learning how to cast for trout as long as your arm.
We pulled into the dusty outpost of Stanley (pop. 70) for a whitewater trip on the raging upper fork of the Salmon River. Isolated from big cities and surrounded by mountains, the area is one of the darkest regions left in the Lower 48 states. During our stay at the Idaho Rocky Mountain Ranch we were blown away by the shooting stars, comets, and meteors that danced nightly across the sky. The MPSA of Stanley is 21.76.
The Central Idaho Dark Sky Reserve is the third largest in the world. A region of remote and largely rugged lands in the Sawtooth Mountains, the Reserve has as its core parts of two recognized wilderness areas, and is situated in the spectacular scenery of the Sawtooth National Forest. With its glacial valleys and 10,000-foot-plus peaks, the Reserve remains a truly "off-grid" experience, with access to neither electricity nor mobile phone service across thousands of square miles. Central Idaho is recognized as one of the last large "pools" of natural nighttime darkness left in the United States.
Due to light pollution, the night sky over many of our cities is hundreds of times brighter than a natural, starlit sky. Most Americans have never glimpsed our home galaxy, or anything but a handful of the night’s brightest stars. A 2016 sky atlas survey revealed that 80 percent of Americans can't view the wondrous band of light known as the Milky Way any longer and the number increases with each passing year as little attention is paid to the types and direction that our artificial lighting gives off.
Founded in 1988, the International Dark-Sky Association is the star loving non-profit dedicated to protecting the night skies for present and future generations. Based in Tucson, Arizona, the organization educates lighting designers, manufacturers, technical committees, and the public about controlling light pollution. The eco-friendly lighting policies foster economic savings, and reduce negative effects of light pollution, such as disrupted sleeping rhythms that effect work production. The use of artificial light also adversely affects the environment and can have negative and even deadly effects on a variety of creatures, including amphibians, birds, mammals, insects and plants.
The international association grants certification for dark sky parks, reserves, and sanctuaries. There are currently 37 official dark sky parks in the United States, 53 in the world. The dozen dark sky reserves have a larger size requirement than parks.
About 50 miles southeast of the town of Stanley on the other side of the Sawtooth Mountain pass is Ketchum — a resort town celebrated as the final home of Ernest Hemingway. After enacting its first ordinance to curb light pollution in 1999, Ketchum was recognized by the IDSA last October as an official Dark Sky Community. Ketchum town officials recruited private landowners and businesses to develop responsible lighting policies as well as an expansive public education to preserve the night sky.
There are naysayers. Dark sky measures have drawn opposition from the outdoor advertising industry and those against additional government regulations.
Still, darkness seekers are growing in numbers. In a singular celestial event, thousands descended on Ketchum for the 2017 summer total solar eclipse. With its awe-inspiring night sky tapestry, the
Central Idaho region is attracting a swelling number of astro-tourists who are looking upwards at those spectacular, star-spangled skies.