Stargazing Live: A tour of the stars and planets of the great southern sky

Updated

Look up! It's Stargazing Live season at the ABC — and you can join astronomer Fred Watson on a guided journey of the Milky Way.

Along the way you'll see beautiful constellations, star clusters, galaxies, and the mighty Jupiter and Moon.

All you need to do is go outside on a clear night between 8pm and 9pm.

Or just put your headphones on, and experience the wonders of the universe while you're on the bus.

For the best experience:

Find a spot away from lights and trees.

Give your eyes 10 to 15 minutes to adjust, then look up and listen.

You'll get the best view if you have binoculars or a telescope.

Turn your phone on to night mode to reduce light interference.

The Southern Cross

The tour begins with the most iconic constellation in the southern hemisphere.

At this time of year, the Southern Cross — or Crux Australis — is upright in the sky between 8pm and 9pm.

You need to look south to see it, but if you're not sure what direction that is the stars will help you.

Scan the sky for the two bright stars Alpha and Beta Centauri. They are about three and a half handspans above the southern horizon. (To get a handspan, stretch your arm out in front of you and it's the distance between your outstretched thumb and little finger.)

Follow the line of the pointers right towards the cross.

The brightest star, at the foot of the cross, is called Alpha Crucis. It's an alpha star, which is the name given to the brightest star in a constellation.

Towards the centre of the cross is the fifth, and faintest star Epsilon Crucis or Ginan, which can be hard to see in areas with lots of light pollution.

While it appears to us like a cross, vast distances separate each of these stars in three-dimensional space.

Hey, if you're reading this, you're seriously missing out

The interactive, audio-driven version of this sky tour is really something special — a celestial tour-de-force. And we don't say that lightly. You really should check it out — tap through and choose the 'get started' button.

The Jewel Box

If you look at the star in the Southern Cross that's closest to the pointers, which is called Beta Crucis or Mimosa, you'll see a real gem.

Sitting just to the left of Mimosa is a beautiful little cluster of more than 100 orange, yellow and blue stars.

In 1830, the English astronomer John Herschel was so enamoured by the cluster, known as NGC 4755, he nicknamed it the Jewel Box.

Through binoculars or a telescope you can make out details of the A-shaped cluster, including a red supergiant star.

The Jewel Box is about 6,400 light years away, so the light we see today was emitted before the Great Pyramids in Egypt were built.

The Emu in the Sky

The Southern Cross and Jewel Box sit in a rich part of the Milky Way. If you are in a dark area on a moonless night, you'll see our galaxy as a band of light stretching across the sky.

This area is also home to one of the best-known Indigenous constellations. The Emu in the Sky is recognised by Aboriginal people across Australia.

It's a constellation made of dark patches in the Milky Way. Between 8pm and 9pm in May, the head of the emu appears as a dark patch just below the Jewel Box to the left of the Southern Cross.

This is the Coalsack nebula — a patch of gas and dust that hides the light from the stars behind it.

The Emu's neck passes between the pointer stars, and its body lies in the constellation of Scorpius further towards the eastern horizon in the early evening.

Omega Centauri

Sitting left and above the Southern Cross at this time of night is another stunning star cluster.

Omega Centauri is the biggest and most massive cluster in the Milky Way. Astronomers believe it may be the core of an ancient galaxy that was stripped of its outer stars.

To find it, scan upwards and to the left (east) until you're at a position that makes an equilateral triangle with the cross and the pointers. It looks like a fuzzy blob, which is quite different from the points of stars.

While it may not look like it to the naked eye, it contains over 10 million stars located about 15,800 light years away.

The stars, which are between 10 billion and 12 billion years old, are so tightly packed they are only about a third of a light-year apart.

That's roughly 13 times closer than the closest star to our Sun.

Carina Nebula

Sitting about half a handspan to the right of the brightest star in the Southern Cross is spectacular Carina Nebula, a huge cloud of dust and gas dotted with bright stars.

One of these is Eta Carinae — a strange double star system surrounded by its own orangey-red nebula.

And it is like nothing else we know of. The bigger star in the system is coming to the end of its life, but its ultimate fate is a mystery.

It exploded in the 1800s, becoming the second brightest object in the sky, but came back to life a hundred years later.

When it explodes again, which could happen at any time, it may become the brightest supernova we've ever seen.

The Diamond Cross and the Southern Pleiades

The Southern Cross is not the only cross in our sky, a fact that sometimes confuses stargazers.

About half a handspan below the Carina Nebula, and about half a handspan to the right of the brightest star in the Southern Cross, is the Diamond Cross.

This is not a constellation, which are strictly defined by the International Astronomical Union; instead it's an asterism — a group of stars that form a pattern or shape. It sits in the constellation of Carina.

The point of the Diamond Cross closest to the Carina Nebula, known as Theta Carinae, is not a single star, but a beautiful open cluster of stars known as the Southern Pleiades. Astronomers give it the much less evocative name of IC 2602.

Discovered by Abbe Lacaille in 1751, it is bright enough to be seen with the naked eye, but binoculars or a small telescope reveal the cluster in more detail.

The False Cross and the Southern Beehive

If you look further to the right of the Diamond Cross you'll see another cross-like asterism, the False Cross.

This often gets mistaken for the Southern Cross, but it is much larger and it doesn't have pointer stars.

Its stars actually belong to two different constellations — Vela and Carina.

If you have binoculars, you can also look for a compact star cluster a little below the right tip of the False Cross. This is NGC 2516 or the Southern Beehive. A telescope will reveal some of the stars are actually double stars.

The Large Magellanic Cloud

If are in a dark sky area on a moonless night, you can use the False Cross to help find one of our galactic neighbours.

Follow the long axis for the False Cross downwards and you'll see a fuzzy patch of light about halfway between the False Cross and the horizon.

This is the Large Magellanic Cloud.

Its neighbour, the Small Magellanic Cloud is close to the southern horizon and is very difficult to see without perfect conditions and a moonless sky at this time of the year.

The Magellanic Clouds are actually dwarf galaxies that are slowly being pulled apart by our Galaxy. They look like they're stray bits of the Milky Way but they're actually not directly connected.

The Large Magellanic Cloud, which is 165,000 light years away, is filled with star nurseries.

The brightest of these is called the Tarantula Nebula — a glowing mass of stars and gas filaments that look like spider legs.

If you are in a dark sky area you can see the nebula using binoculars or, even better, a rich-field telescope.

Sirius

Sirius is the brightest star in the sky — and at this time of year it is sitting almost due west.

To find it, head right from False Cross (past Canopus the second brightest star in the sky, near the foot of the False Cross) and you'll see it sitting low on the western horizon.

Known as the Dog Star because it sits in the constellation of Canis major, Sirius is also the ultimate twinkling star. This effect is due to turbulence in the Earth's atmosphere breaking up the star's light into different colours of the spectrum.

This colourful twinkling is particularly noticeable when the star is close to the horizon, as it is at this time of year, when it sets at about 9:00PM.

The Moon

The brightest object in the night sky is the Moon. The subject of a multitude of love songs and conspiracy theories, it is hard to miss — most of the time.

The only time you can't see the Moon is during the new moon phase, when it is close to the Sun in the sky.

This year during Stargazing week, the Moon will be at first quarter, which means it is a quarter of the way through its cycle and half of its face is lit.

Even the most modest binoculars will reveal the Moon's bigger craters, especially when they are illuminated obliquely by the Sun, as they are at first quarter.

It's also easy to make out the grey areas, known since ancient times as 'seas', but which are actually basaltic lava flows.

At 8pm it sits in the north-west near the constellation of Leo. As the week progresses it appears higher in the sky towards the east as it brightens towards the full moon at the end of the month.

Leo

The zodiacal constellation of Leo dominates the heavens at this time of year — although it will be a bit dimmed during Stargazing Live week because of the Moon.

The bright stars in Leo make up a stick-figure lion — at least in the northern hemisphere. It is upside down in the Southern Hemisphere.

The constellation is named after the mythological monster killed by Heracles but it was also depicted as a lion in much earlier cultures across the Near East.

The group of stars representing Leo's head and forepaws is shaped like an upside-down question mark and is often called the Sickle.

At the base of the question mark is Leo's brightest star — Regulus — which means 'little king'.

Regulus is actually a double star. If you look through binoculars, you may be able to spot its fainter companion.

Leo is also home to some spectacular galaxies that are visible through small telescopes. One of these is spectacular spiral galaxy called M66. It is part of a trio known as the Leo triplet.

Jupiter and Saturn

Jupiter is the largest planet in our solar system — it's a gas giant with a mass more than double that of all the other planets in our solar system combined. It also has lots of moons, 67 that we know of.

Jupiter sits in the north-eastern sky around 8pm in late May this year.

Like the moon its position against the background stars changes over time as it moves along a line called the ecliptic.

It forms a lovely triangle with two prominent stars in the northern sky: Arcturus, the brightest star in the constellation of Bootes; and Spica, the brightest star in the constellation of Virgo.

If you have binoculars or, even better, a telescope, you will be able to make out Jupiter and, nearby, one or more of its four largest moons: Ganymede, Callisto, Io, and Europa.

By 9pm as Jupiter moves higher in the north-eastern sky, you will also see Saturn as it rises above the eastern horizon in the constellation of Sagittarius.

If you have a telescope you should be able to make out its rings. Even binoculars can reveal Saturn’s elongated shape due to the rings.

That brings us to the end of our May night sky tour. Remember: the night sky is always there for all to see. All you need is clear weather and a little patience to find your way among the stars.

About your guide

Professor Fred Watson is a well-known astronomer, author and science communicator. Working at the Australian Astronomical Observatory, he is passionate about preserving dark sky spaces so everyone can enjoy the night sky.

Credits

Reporter, producer: Genelle Weule

Astronomer & narrator: Fred Watson

Audio producer: Maria Tickle

Audio engineer: Richard Girvan

Designer, photo illustrations: Ben Spraggon

Developer: Colin Gourlay

Editor: Matt Liddy

With many thanks to our community of remarkable astrophotographers: David Malin, Mike O'Day, Anthony Wesley, River Petein, Steve Crouch, Suavi Lipinski, Padraic Koen, Michael Worthington, Bruce Bull, Joe Perulero, Diego Collonello, James Garlick and Krusty Ed.

Want more science from across the ABC? Like us on Facebook

Follow us on Twitter

Subscribe on YouTube Science in your inbox Get all the latest science stories from across the ABC. Sign up

Topics: science-and-technology, astronomy-space

First posted