Alberta’s Rothney Observatory telescope images being threatened by light pollution

The 1.8-metre ARCT telescope at Alberta’s Rothney Astrophysical Observatory is the second largest in Canada, used by both astronomers and students to capture images of stars millions of light-years away.

But as Calgary expands, those images are being threatened by excessive artificial and outdoor light also known as light pollution.

RAO’s education specialist Jennifer Howse said light pollution in Alberta has worsened over the past few decades.

“Quite embarrassingly, Edmonton and Calgary are extraordinarily bright compared to other centres… It’s not something to be proud of,” she said.

“As the city expands, I would go so far as to say it’s a threat to the observatory… We haven’t been efficient in our lighting design, and essentially, we’re lighting up the sky.”

Howse said telescopes can be blinded by too much light.

“If we have too much other white light in the surrounding area, that would mean we wouldn’t be able to collect that white light that we’re after,” she said.

About 15 kilometres away from the observatory is a new subdivision planned for the city.

Once fully developed, Providence will border Bridlewood and Evergreen in the southwest. Astronomers are concerned about increased light pollution once homes are built and street lights are installed.

Phil Langill, a University of Calgary professor and director at the observatory, said the university is working with the city to reduce light pollution and ensure the skies remain dark. The school has recommended the use of motion sensor lights.

“With new communities, they’re trying to do what they can to reduce the amount of light,” Langill said.

According to the city, Providence has been identified as a special geographical region. 

“This will be achieved through using a proposed luminaire that features the lowest possible colour temperature while conforming to City of Calgary specifications. This project will not only have an impact on the surrounding natural landscape but should provide benefits for future residents of the area as well,” read a statement from the city.

Officials will apply specific lighting designs that respect the exterior environment, the city said.

Our goal is to mitigate light pollution and preserve dark skies in the Providence area due to its proximity to a nocturnal preserve and the Rothney Astrophysical Observatory,” the city said.

Foothills County has had a “Dark Sky” bylaw for the past 10 years. The county requests lighting on all new builds in the area to be downward-shining. Residents must also replace “offensive lighting” when there is a complaint.

“In no way are we diminishing a resident’s right to light. Just use what is needed on the property, shine it downward and keep the light from trespassing, extreme brightness and offending neighbours,” Foothills County reeve Suzanne Oel said.

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