This article is more than 5 years old

This article is more than 5 years old

Siding Spring, Australia’s premier observatory, could be forced to shut down due to light pollution from a series of planned coal seam gas developments in the area, astronomers have warned.

The site of the Australian National University’s observatory, near Coonabarabran in New South Wales, currently benefits from clear, dark skies above it.

This environment allowed the observatory’s powerful SkyMapper telescope to discover the oldest known star, at 13.6bm years old, earlier this year. Siding Spring also gave its name to a comet that had a close shave with Mars on Monday.

But three proposed gasfields around 50km away could render the observatory useless, due to the amount of light the developments will cast into the night’s sky. Astronomers need dark skies in order to pick out stars and other celestial objects in space.

Mining firm Santos plans to tap the area, known as the Gunnedah Basin, for gas. This area includes the Pilliga forest, which has seen exploration met with fierce protests. Test drilling has already taken place in Narrabri.

A map showing proposed Santos gasfields. Photograph: Santos

As well as light pollution, astronomers are concerned that material dispersed from mining operations will be corrosive to telescope lenses. Siding Spring has around 50 high-grade telescopes pointing at the heavens.

Peter Small, who provides technical support for Siding Spring, said an existing mining operation at Boggabri already gives off more light than the neighbouring towns of Narrabri and Gunnedah.

“We get light pollution from that – we even get light pollution from Sydney, which is 400km away, so you don’t have to be that close,” he said.

“This will reduce visibility. If there’s light pollution from anywhere, never mind about the gasfields, this site becomes unviable. It would shut down and all those local jobs would be lost.

“I’d hope there would be a compromise, but no dialogue has taken place with Santos as yet.”

Observatory staff want Santos to commit to burning off gas, called flaring, during the day, rather than light up the night’s sky with flames.

Rob McNaught, a retired astronomer who discovered the Siding Spring comet that passed close to Mars, said he was not confident this would happen. McNaught has been looking at stars in the area for the past 30 years, discovering 82 comets in the process.

“It appears the laws are so piss-weak that Santos can do what they like,” he told Guardian Australia. “This light pollution would have a major impact and make a mockery of having Australia’s largest observatory here.

“The cultural significance of this area, the thing that brings people from around the world with their telescopes here, would be destroyed.”

The light from a gas flare at Narrabri seen against the August supermoon. Photograph: Supplied

Santos said it is currently putting together an environmental impact statement (EIS) that will identify all potential effects of its coal seam gas expansion.

“We appreciate the Siding Spring community has some concerns, however, when the EIS is public all interested parties will have the opportunity to review and assess the actual impacts rather than speculate on potential impacts,” a Santos spokeswoman said.

“As part of the EIS process, consultation will take place and the public will have the opportunity to review the document and present formal submissions to the government.

“Santos is committed to ongoing communication and engagement with the community and is always available to meet with interested parties and address their concerns.”

The Siding Spring survey, named after the observatory, was the only program in the southern hemisphere actively searching for potentially hazardous comets, asteroids and meteors before its funding was cut last year.