Rich pickings when you look to the west

The Milky Way is a barred spiral galaxy that includes our solar system, which is about 26,000 light-years from the galactic centre. Our galaxy probably contains 100 to 400 billion stars, and is about 100,000 light-years across and just 1000 light-years thick. Photo: MPAS member Kelly Clitheroe

There are a few interesting targets in the sky at the moment in Aquarius. The globular cluster M2 appears as a fuzzy star through binoculars and is near the star Beta Aquarii. And the planetary nebula NGC 7293, the Helix Nebula, appears as a faint fuzzy disc through a small telescope. Another globular cluster, M15, in Pegasus, is thought to be 13.2 billion years old and can be picked out with binoculars, while a small telescope shows it clearly.

Lying in the constellation Tucana, the Small Magellanic Cloud can be found close to the beautiful globular cluster 47 Tucanae, also known as NGC 104, which is a must-see target in the September southern skies. It is visible to the naked eye as a hazy star, but a small telescope shows its bright centre and many of its glittering stars. This cluster is 15,000 light-years away. Other visible targets include the globular clusters M22 in Sagittarius, NGC 6397 in Ara, and M4 in Scorpius. The open clusters M6 and M7 in Scorpius are also visible.

And be sure to enjoy the rich regions of Scorpius and Ophiuchus this month before they sink below the western horizon. Just above them lies another rich region around the heart of the Milky Way galaxy, brimming with star clusters and bright nebulae. In contrast, the eastern half of the sky is relatively empty, although you can still find several constellations, including Pisces, the Fishes; Cetus, the Whale; and Eridanus, the River.

On September 8, Saturn will be at opposition, which is when the sun is on the opposite side of the sky from the outer planet – or, to be more technical, when the sun and the planet are exactly 180 degrees apart in the sky. It is also when the planet is at its general closest position to Earth. Then on September 22 the Earth is at equinox, which is when the sun shines directly on the equator and the lengths of day and night are nearly equal.

By Nerida Langcake
This article appeared in the September 2024 issue of the Mornington Peninsula Magazine.