A guide to what's up in the sky for Southern Australia

Previous Articles

Starwatch for June 2026 (1st Jun 2026)

The winter Milky Way shines across the sky from east to west in a blaze of starlight.

Roaming through the Milky Way with binoculars is an amazing experience. It’s like canoeing down a river of golden stars. When we look towards Sagittarius, halfway up the eastern sky, we are looking towards the centre of our galaxy where just about all the stars are old stars and hence cooler. The star colours here are therefore predominantly reddish yellow, whilst the stars in the outer edges of our galaxy are blue and white, advertising their relative youth and energetic spirit.

A myriad of other bright stars adorn the late-evening sky right now. Blue-white Regulus, the heart of Leo, the lion, stands half-way up the north-western sky. Yellow-orange Arcturus, one of the brightest stars in the night sky, is well up in the north-east. And all around the heavens, you'll see many other stars in shades of blue, white, yellow, orange, and red.

Each instant that you watch one of these stars, you're participating in the end of a long journey - a journey that began deep inside the star.

Starlight is created in the heart of a star, where atoms join to create heavier atoms, plus a "packet" of energy called a photon. Few if any of the photons born inside a star make it to the surface. They ram into atoms or other photons, triggering the creation of new photons. Thousands of years after a photon is born inside a star's nuclear furnace, some of its descendants finally reach the surface.

Once there, they rush into space at the speed of light. Photons come in different colours, which reveal the temperature of a star's surface; blue stars are the hottest, red stars are the coolest.

Eventually, some of the light that left Regulus or Arcturus makes its way to Earth. As you look up, some of the starlight strikes your eye - and its journey is at an end.
But the photon triggers one last reaction. A nerve impulse travels to your brain, telling you that you've just seen one of the wonders of nature: a star.

Two bright stars, high in June’s evening sky have a lot in common. Antares, and Spica are among the biggest, brightest, and heaviest stars in the galaxy. And each one will end its life with a titanic explosion known as a supernova.
Antares is the orange heart of Scorpius, which is high in the east. The light from Antares has been travelling since Christopher Columbus left to discover the Americas in the 1490’s. And blue-white Spica is the leading light of Virgo, high in the north. At 260 light years distant, the light from Spica began its journey to Earth when Lieutenant James Cook became the first European to map and claim the east coast of Australia in 1770.

Both stars are doomed because of their mass. Each is more than 10 times as massive as the Sun. Because of that great heft, gravity squeezes their cores tightly, heating them to billions of degrees.

At those temperatures, nuclear reactions in the core furiously convert lighter elements into heavier ones. But when the core is converted to iron, it takes more energy to continue the process than the core can produce.

At that point, the reactions stop and the core collapses to form a neutron star — an ultra-dense object that’s a few times the mass of the Sun, but only about as big as a city. The star’s outer layers fall in toward the core, then rebound. That creates a shock wave that rips through the surrounding gas — and blows the star apart.

The smallest constellation in the night sky is found high in the south during these cold winter nights. It is also one of the most famous. Its correct name is "Crux", the cross, although it's better known as the Southern Cross. Its stars are shown on the Australian and NZ flags.






Crux is small, but it's packed with celestial wonders. For example, there's the Jewel Box Cluster, shown on this month’s starchart by its catalogue number of 4755. Seen through a telescope, the stars of the Jewel Box shine diamond-white and sapphire-blue. A lone red star lies between Earth and the cluster, so it looks like a ruby against the other gems. The whole cluster is set against the glittering band of the Milky Way. Of course, you’ll need a dark sky to see the Milky Way. The light polluted skies of Adelaide hide it.

Surrounding the Southern Cross on three sides is the constellation of Centaurus, the centaur. Its two brightest stars, Alpha and Beta Centauri, (labelled with the Greek letters α and β) are referred to as the Pointers, because they follow the Southern Cross around the sky and always point to it. Alpha Centauri is actually the closest star system to the Earth other than our own Sun, at a distance of just over 4 light years.
Unless you’re an early riser, the only planetary action in the evening sky occurs in the west soon after sunset. The planets Venus and Jupiter meet each other in the arms of the constellation, Gemini on the evening of 9 June. They are only separated in the sky by 1.7o, but the true separation is huge. Venus is only 179 million kilometres away, whilst Jupiter is shining at us from a whopping 788 million kilometres.
Mercury completes the trio of planets. It looks like a fairly bright star. But it’s so low that you need a clear horizon to spot it. You’ll find it between the legs of Gemini..

Mercury, the Sun’s closest planet has no air, only a few atoms captured from the solar wind, or knocked off the surface of Mercury by the solar wind. And even that is a hard vacuum by Earth standards. Mercury is zapped by solar energy. That heats the dayside to as high as 450oC.

The Moon is at Last Quarter on June 8th, at New on the 15th, at First Quarter on the 22nd, and Full on June 30th.

Happy observing!