The Royal Astronomical Society of Canada is compiling a guide to how hundreds of cultures used the stars with the World Asterisms Project.

Led by RASC first vice-president Charles Ennis, nearly 6,000 asterisms from more than 400 cultures had been recorded when he was interviewed in February. Smaller guides for specific cultures have been published, but the RASC guide spans continents.

“It’s a massive undertaking but what we’re trying to do is let people know there are other views out there,” Ennis said.

The project launched in June 2021 with the goal of celebrating the world’s sky cultures. A handbook will be available on the RASC website this year. It will be updated as new discoveries are made.

These asterisms are key to understanding our past, Ennis argued. The project records how different civilizations have used asterisms as calendars, navigational aids or harvesting schedules. There are epic battles, divine judgements, heroes, villains and ancestors.

“The sky reflects the Earth. People put their calendar in the sky. Your ancestors, your gods and the things symbolizing your culture are up there,” Ennis said. “There were all kinds of things people used the sky for that they now use their cell phone for.”

Many patterns do not use the connect-the-dot format of modern constellations. In the skies above ancient China, for instance, star clusters tell stories and each star is a character. Some cultures use dark patches of the Milky Way and others pay attention to how stars flicker.

There is a sense of urgency to the project. The legacies of colonialism means written records of asterisms for different civilizations are rare.

The number of people with generational knowledge is shrinking. Ennis said finding African astronomers and experts to contribute to the project has been hard, but in Australia research teams are studying the asterisms of dozens of Indigenous peoples.

“We would prefer that people from their own cultures represent their skies,” he said. “It’s a matter of trying to track down Elders or remembering the stories of Elders so you can reassemble these things.”

Another hurdle is progress. Light pollution is turning the night sky into a purple-orange haze in many cities. In places where stars are still clear, space junk and an increasing flood of satellites crowd the sky.

“We cannot go back to some golden age where everyone saw the same night sky, because that has never happened and it never will. You might look at a pattern and say ‘that looks like the Big Dipper,’ but if you’re Basque that’s the shepherd,” said Ennis. “This might be a way to get people to know there’s more than one way to see things, and to start looking up again and decide they should be able to see the night sky again.”