A photo taken from the International Space Station (ISS) clearly shows the impact of Calgary's transition to LED streetlights.
American astronaut Scott Kelly, who is on a year-long mission on the ISS, posted an aerial photo of Calgary to Twitter Saturday, with the caption "#GoodMorning #Calgary and all my friends in #Canada!"
Comparing Kelly's photo to the one Canadian astronaut Chris Hadfield took in 2013, it's easy to spot the neighbourhoods that have changed most in two years.
Calgary started transitioning from high pressure sodium vapour lamps (HPS) in September, with the goal of replacing 80,000 of the city's streetlights by 2018. So far, 21 communities have gone LED — a rate of about 2,000 lights replaced per month.
LED lights have a cooler hue, and produce less upward light pollution than their orange-hued HPS counterparts.
The Rothney Astrophysical Observatory, located just outside Calgary, has pushed for a transition to properly shielded and directed lighting to make it easier to observe the night sky.
The new lights are not only more energy efficient, but they're also expected to save the city approximately $6 million per year.
Check out the photo below to spot the neighbourhoods that have converted to LED: