It seems just like yesterday that we greeted the return of the summer stars to the evening sky, and here we are in March, getting ready to wave goodbye!!

So, let’s introduce some of the Autumn stars and constellations. The Milky Way stretches from the northwest to the southeast, crossing directly overhead. In the southeast, Crux, the Southern Cross, is very conspicuous. The two Pointers, Alpha (α) and Beta (β) Centauri can be found immediately below it. They are known as the Pointers because, as the Southern Cross and the Pointers rotate around the South Celestial Pole, they always point to the Southern Cross.

Alpha Centauri, the lower and brighter of the two Pointers, is actually one of the closest stars to our Sun, at a distance of only 4.25 light years. It is also one of the most spectacular sights in the sky when viewed through a telescope. Alpha Centauri really consists of two stars which are almost identical twins of our own Sun, and a third star, Proxima Centauri, that orbits around the common centre of gravity on a journey that takes several million years. The two main stars revolve around each other every 80 years.

Beta Centauri looks only slightly fainter than Alpha Centauri, so that the logical conclusion would be that it must be at about the same distance from us as Alpha Centauri. Wrong! Beta is a much brighter star that is over 200 times further away.

Prominent in the northeast is the constellation of Leo, the Lion. A pattern of stars that looks like an upside-down question mark forms Leo's head and mane. The bright blue-white star at the top of this pattern is Regulus, the lion's heart.
Looking to the west from Regulus, looms Cancer, one of the faintest constellations in the sky. As if to make up for its lacklustre showing of individual stars, Cancer sports a beautiful star cluster. From a dark spot, making sure there’s no moonlight, scan the night sky right in the middle of Cancer. What the eyes alone see as a faint blur, binoculars pick up as a sparkling scattering of gems: the Beehive star cluster (M44).

The constellation of Eridanus, the river, is high in the western sky as night falls. It begins near Rigel, the bright star at the foot of Orion. It then makes as many twists and turns as most earthly rivers before reaching its first “end,” Acamar. After that, it keeps going until it reaches the final end, Achernar. And both star names mean “the end of the river.”

In fact, that’s exactly why Eridanus has two end-points. From the latitudes of ancient Greece, where the constellation was drawn, skywatchers could see only down to Acamar; everything else remained below the horizon. So, Eridanus ended right there.

Centuries later, though, European ships sailed into the southern hemisphere. Crew members saw a much brighter star down to the lower left of Acamar, so they added it to the outline of Eridanus. And they gave it a nearly identical name, Achernar, giving the river a brighter end.

With the coming of Autumn, we bid farewell to the Pleiades star cluster, also famously known as the Seven Sisters.

Many ancient cultures had myths and stories associated with the Pleiades. In Greek mythology, the Pleiades were the seven daughters of Atlas, a Titan who held up the sky, and the oceanid nymph Pleione, protectress of sailing. The sisters were Maia, Electra, Alcyone, Taygete, Asterope, Celaeno and Merope.
According to a Polynesian legend, the Pleiades was once a single star: the brightest in the sky. The Polynesian god Tane disliked this star bragging about its beauty. The god smashed the star into pieces, creating the Pleiades star cluster.

The Seven Sisters story is also written into the marriage law of the Nyoongar first nations people of Western Australia. Approximately every 14 years a significant event known as Yokalarang occurs. It is signalled by the conjunction of Yokalar, the planet Jupiter, with the Pleiades constellation. It next occurs in 2036. Girls born, during that Nyoongar year, go through a process that determines which of them will sacrifice their genes and be married to the Yamatji people to the north and the Wongai people to the east. This practice, governed by marriage law, ensures Nyoongar, Yamatji and Wongai gene pools remain strong.

Although the core of the cluster contains some 100 bright stars, the total number of stars may be closer to 400 as many lower mass members have been identified recently. The central core radius of the cluster is only about 4.5 light-years, but the remote outer regions of the cluster may extend out as far as 52 light years from the centre. The brighter members of the cluster are blue stars with temperatures of 20,000 degrees.

Studies show that the stars were born from the same cloud of gas and dust some 100 million years ago. This gravitationally bound cluster of several hundred stars is located 440 light-years distant. Also, these sibling stars drift through space together at about 40 km per second. Many of these stars shine hundreds of times more brightly than our sun. Because of its size in the sky, the cluster is best observed with binoculars.

A new comet was discovered in mid-January that could put on quite a show for us in early April. I will provide more details in next month’s article. Known as comet C/2026 A1 MAPS, it is a sungrazer comet, and believed to be a fragment of a huge comet which appeared in 371BC, aka Aristotle’s Comet. Comets are very unpredictable. We won't really know how bright it will be or if it will survive its close encounter with the Sun. Stay tuned!

A total Eclipse of the Moon occurs on the evening of March 3. The Full Moon rises in the north-east at 7:42pm, just as the Sun is setting in the west. Whilst still in twilight, at 8:20pm, the Moon begins to enter the Earth’s shadow. Within minutes, the limb of the Moon starts to darken. The shadow marches across the face of the Moon, until 9:34pm, when the Moon enters the umbra, the darkest part of the shadow. We now have a Blood Moon. The depth of colour will be governed by the sunsets and sunrises around the world. The stars that would normally have been hidden in the bright moonlight sparkle in the darkened sky. The Milky Way is now clearly seen overhead. It takes the Moon 1 hour to travel through the umbra. At 10:32pm, the sky begins to brighten again. The changing appearance of the Moon during eclipse is shown below. All times are in ACDT, please adjust to your local time zone.

The Moon is Full on March 3, at Last Quarter on the 11th, New on the 19th and at First Quarter on March 26.