The light pollution on Nantucket is not as bad as in many other places, but it's growing at an alarming rate. Do you ever look up at the Milky Way and worry that your children or grandchildren might not be able to do that? If we're not careful, that could happen.
"Here on the island of Nantucket, 30 miles out to sea, we’re blessed with dark skies. For now.
Seen from space today, Nantucket glows like a firefly in the night. Our view of the starry skies is at risk of slowly, imperceptibly, disappearing. It’s estimated that two-thirds of Americans can no longer see the Milky Way at night because of the glare of artificial lights where they live. Light pollution not only spoils our view of the night sky, it also affects our health, wastes resources, and impacts other creatures on our planet.
Fortunately, there are still plenty of places on Nantucket where it’s possible to see stars from horizon to horizon. But if we don’t work together to preserve our dark skies, we’ll lose them."
Maria Mitchell Association website, https://www.mariamitchell.org/the-dark-night-sky
Orbiting satellites have mapped how much light is shining upward from the ground below. Here’s what Nantucket looks like as seen at night from space, based on data available in April 2020.
Between 2012 and 2020, light pollution on Nantucket increased at a rate of 2.4% each year -- which means that in 2020, we had nearly 20% more light pollution than we had in 2012.
Let's make Nantucket an EXCELLENT DARK SKY SITE!
The Bortle Scale
The Bortle scale is a nine-level numeric scale that measures the night sky’s brightness of a particular location. It quantifies the astronomical observability of celestial objects and the interference caused by light pollution. John E. Bortle created the scale and published it in the February 2001 edition of Sky & Telescope magazine to help amateur astronomers evaluate the darkness of an observing site, and secondarily, to compare the darkness of observing sites. The scale ranges from Class 1, the darkest skies available on Earth, through Class 9, inner-city skies.