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

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Starwatch for September 2026 (7th Sep 2026)

Spring is just around the corner, and with it, comes the promise of warmer evenings and clearer skies. And hopefully the opportunity to spend more time looking up!

All 12 constellations of the zodiac are well known. But thanks to a popular '60s song, the most famous is Aquarius, the water-bearer. You can find it high in the eastern sky. Try looking for the stars of Aquarius on a dark night, as moonlight will overpower many of the constellation's fainter stars, but the brightest ones will still shine through.
Almost all major ancient civilizations saw Aquarius as a man or boy carrying a bucket of water. People have always placed special significance on Aquarius and the other constellations of the zodiac because they lie along the ecliptic; the path that the Sun follows through our sky.

In fact, that's what "the age of Aquarius" is all about. About 600 years from now, the Sun will appear in Aquarius at the time of the March equinox. But that's about the only significance for Aquarius and the other zodiacal constellations; they're good guideposts to help mark the seasons. They have no special influence over our daily lives.

Look up in the early evening, and you'll be greeted by the heart of our Milky Way galaxy almost directly overhead. You'll see the unmistakable form of Scorpius, the Scorpion, and the group of stars that make up the constellation of Sagittarius, the Archer. Look carefully in this area of the sky and you'll notice the misty glow of the countless millions of stars that are too far away for us to see clearly. Their light has journeyed for more than thirty thousand years to reach us.
As you scan the Milky Way, you’ll notice vast rifts that don’t seem to contain any stars. These rifts are actually enormous clouds of gas and dust that hide the Milky Way’s stars behind them. It’s not that there are no stars, they are just hidden from our view. The giant clouds of gas and dust will one day condense and form new stars.

Look low to the north. A beautiful blue-white star awaits. Vega is one of the closest and brightest stars in the night sky. It was one of the first stars whose distance was measured. The measurement has been refined since the 1800’s, and today astronomers know the distance quite precisely: 25 light-years. That means the light we see from Vega today left the star in 2001.

Look to the right of Vega and locate the stars that make up the constellation of Cygnus, the Swan. This star grouping has been identified with some sort of bird by most civilizations of the ancient world. Sometimes known as an eagle, a hen or a pigeon; the image of a graceful swan in full flight is the one I prefer. The star Deneb represents the tail of the swan, whilst Alberio is the beak.
In real life, Deneb is a star of enormous proportions. It is over 60,000 more luminous than our Sun, and 25 times more massive. If we placed our Sun at the same distance that Deneb is from us (1600 light years), then the Sun would be an insignificant little star barely visible in large amateur telescopes.
Alberio is a beautiful double star of blue and gold. A steadily held pair of powerful binoculars should show it as two distinct stars.

Higher in the sky we find Aquila, the Eagle. The brightest star in this constellation is Altair. At a distance from us of only 16 light years, it definitely classifies as a close stellar neighbour. But a bit of a strange character! It is about twice the diameter of our Sun, but spins on its axis in 6 and a half hours (our Sun takes 25 days). As a matter of fact, the spin is so rapid, that the star probably resembles a flattened tomato!
You might expect our closest neighbouring star to be one of the brightest lights in the night sky. Instead, though, it’s so faint that it wasn’t discovered until over a century ago, in September 1915. Now known as Proxima Centauri, it’s just four-and-a-quarter light-years away.

If all the stars were as bright as the Sun, nearby stars would be easy to find, because they’d shine the brightest. But most stars are red dwarfs, which are so faint that not a single one is visible to the unaided eye.

Proxima Centauri was discovered by Robert Innes. He was born in Scotland but journeyed to South Africa to observe the southern sky. He made his great find by examining photographic plates taken on two different nights; one in 1910 and the other in 1915. Innes alternated the view from one plate to the other. In this way, he spotted a dim star that shifted position during the five-year interval, a sign the star was close by.
The new star was quite close to Alpha Centauri, which was the closest-known star system. What’s more, the new star seemed to be moving in the same direction as Alpha Centauri, which suggested they might be related. Sure enough, when astronomers measured it, they found it was nearly the same distance as Alpha Centauri.
It turns out that the star is actually a member of the Alpha Centauri system. But it’s a bit closer to us than the system’s other two stars, hence its name: Proxima Centauri, the closest star to the Sun.

Proxima Centauri has three known or candidate planets orbiting it. These worlds are the closest known exoplanets to our solar system. Proxima Centauri b is a rocky, Earth-sized planet with a mass similar to Earth. It orbits inside the star's habitable zone, but heavy solar flares from the star make it hard to know if it can hold an atmosphere or water. Proxima Centauri c is a larger candidate planet that sits much farther out, though its exact existence is still debated by scientists. Proxima Centauri d is a very small planet weighing about a quarter of Earth's mass. It hugs very close to the star and completes an orbit in just five days.

Let’s return closer to home. Building the planets of the solar system was like building a city, it didn’t happen all at once. Instead, it probably took a hundred million years or more to complete the construction project.
The first to be completed were Jupiter and Saturn, the Sun’s largest planets. They came together in the prime real estate for planet building – the region with the most raw materials. Closer to the Sun, it was so hot that ices were vaporized and blown away. Farther from the Sun, the material thinned out. But at the distance of Jupiter and Saturn, the balance was just right.

The two giants took shape in a hurry. Small grains of ice and rock stuck together to make pebbles, then baseball-sized chunks, then boulders, and so on. That quickly built massive cores, which then swept up huge amounts of leftover hydrogen and helium gas. So, within just a few million years, Jupiter and Saturn grew to monstrous proportions.

Saturn consists of a series of layers. Its core is a dense ball of metal and rock. Around that is a layer of hydrogen that’s squeezed so tightly that it forms a metal. Around that is a layer of liquid hydrogen – the lightest and simplest chemical element. And the planet is topped by an atmosphere that contains methane, ammonia, water, and other compounds.

Despite its great size, Saturn spins once every 10.7 hours. That pushes material outward, making the planet fatter through the equator. The combination of its composition and rotation makes Saturn especially light, it’s less dense than water. If we could find a bath large enough, we could float Saturn in it.

Stargazers have been eagerly awaiting Saturn’s return to the evening skies to get a view of its magnificent rings. You can find it low in the eastern sky between the constellations of Pisces and Cetus. The planet's rings were first observed by Galileo Galilei soon after the invention of the telescope in 1609. While the other three Jovian planets (Jupiter, Uranus and Neptune) have since been discovered to have rings, they’re faint and no match for the magnificent system around Saturn. Since crossing the planet’s ring plane in March 2025, we now get a view of their southern side. This aspect will continue as the rings gradually open up until the next passage of the Earth through the ring plane in 2038.

The Moon is at Last Quarter on September 4, at New on the 11th, at First Quarter on the 19th, and Full on September 27th.