August: Archer a tempting target for astronomers

NGC 6729 – also known as Caldwell 68 – is a reflection/emission nebula located about 400 light-years away in the constellation Corona Australis, making it one of the closest star-forming regions to Earth. Photo: MPAS member Nik Axaris

In the August skies you can find Sagittarius, the Archer, lying almost overhead; to its south-west lies Scorpius the Scorpion. When you look towards these constellations on a clear night, you are looking in the direction of the very heart of our galaxy, the Milky Way.

With the rich regions of Sagittarius and Scutum visible high in the sky, you can pick up a pair of binoculars and wander along the Milky Way from Scutum to Centaurus. The constellation Scutum, the Shield, is relatively small – the fifth smallest of 88 constellations. It is located between the stars of Aquila and Sagittarius, quite close to the constellation Serpens Cauda, the Snake’s Tail, in a wonderfully rich and interesting part of the Milky Way.

The star field M24 in Sagittarius makes a great binocular target. Looking north, you will find the planetary nebula M57, or the Ring Nebula. It is an interesting target for a small telescope, as is the larger planetary nebula M27, or the Dumbbell Nebula, in the constellation Vulpecula, the Fox.

Also looking north, the constellation Cygnus, the Swan, is home to two open clusters that make good small telescope targets. M29, also known as the Cooling Tower Cluster, is a quite small, bright, open cluster of stars and sits very close to the star Gamma Cygni, officially named Sadr. And the cluster M39 can be seen sparkling against the stars of the Milky Way. It has about 30 stars, covers an area of similar size to the full moon and lies 825 light-years away. Higher in the sky you will find Capricornus, the Sea Goat, which is home to the globular cluster M30 and Beta Capricorni, a double star of magnitude 3.1 that can be seen with binoculars.

This month’s conjunctions, which is when two astronomical objects appear close to each other in the sky, include Jupiter and Mars on August 15, the moon and Saturn on August 21, the moon and Jupiter on August 27, and the moon and Mars on August 28. Also, the moon will pass in front of Saturn on August 21, creating a lunar occultation.

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