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Posted: 2017-12-15 07:58:20

Call it a symptom of our modern age. Thanks to a new sky atlas developed by Australian astronomers, we can now look to the skies without ever glancing away from our screens.

Using more than 70,000 ultra-high-resolution images painstakingly shot over 15 months, astronomers have created the most detailed map of the southern sky ever made – and from Thursday it's available to the public.

The most detailed map of southern night sky

Australian National University astronomers have created the most comprehensive map of the southern sky.

The map captures nearly 300 million stars and galaxies and shows the universe from our viewpoint in incredible detail. It allows users to pick a point in the southern sky and view galaxies in high resolution – or zoom back and appreciate the whole scope of the visible universe.

The astronomy team liken it to a treasure map of the heavens, full of secrets waiting to be discovered – by both scientists and backyard astronomers alike.

"It is the best ever created," says lead researcher Dr Christian Wolf from the Australian National University.

"We wanted to build a digital reference map of the whole southern sky. It's a bit like a library. When someone in the future looks at the sky, they can compare it to this map and check if it's there already or it's something new."

One particular point of interest includes images of the oldest known star in the universe, an ancient ancestor of our sun identified by its perfect rainbow glow.

There are also striking images of quasars – black holes that produce a glow brighter than any other object in the universe as they compress and destroy nearby stars – plus our nearest galaxy and its accompanying globular cluster.

A map of the heavens

The map was built using SkyMapper, a telescope custom-built for just this project, which is based at Siding Spring Observatory in northern NSW.

This image, from the SkyMap, shows our side-on view of the Milky Way.

This image, from the SkyMap, shows our side-on view of the Milky Way. Photo: ANU SkyMapper

SkyMapper captures massive images of the galaxy with its nearly-270-megapixel camera – that's about 11 times the resolution of a high-end professional camera. The images are then stitched together to create the sky atlas.

But while the map has already reached record levels of detail, it's a long way from done yet. The final map, which will be finished in three to four years, will show stars 50 times fainter than those in the current beta version of the map.

If you find a really pristine star with a perfect rainbow, you know it's one of the oldest stars.

Dr Christian Wolf

The oldest star in the universe

When you photograph the entire night sky you're bound to turn up something interesting, but SkyMapper surpassed all expectation when it spotted one of the universe's ancients – a star that formed soon after the Big Bang, 13.7 billion years ago.

Astronomers identify stars by their "rainbow", the different wavelengths of light they give off as they burn, says Dr Wolf. Stars glow slightly different colours depending on what they are made of.

New stars, like our sun, tend to be filled with a mix of matter from across the galaxy – think of it as interstellar gunk the sun has accumulated and now has to burn.

When the universe was young, there wasn't much gunk around, just clean helium and hydrogen. That means older stars are much cleaner than those younger. "If you find a really pristine star with a perfect rainbow, you know it's one of the oldest stars because it has no heavy materials in it," says Dr Wolf.

The star discovered, some 6000 light years away from Earth, glows with a "pure" rainbow. It's a perfect star, says Dr Wolf.

Where to look tonight

Unfortunately, you cannot see this star with the naked eye – it's simply too far away.

Instead Dr Wolf suggests those without telescopes head outside about 10pm and look east, where you can pick out two small, hazy clouds in the sky.

These are the Large and Small Magellanic Clouds, the closest galaxies to our own.

Slightly to one side you should spot their accompanying globular cluster of stars, known as 47 Tucanae. To the eye it looks like a noticeably misshapen star, twinkling thousands of light years away.

Once you've spotted it in the sky, head over to the sky atlas for a close-up.

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