August: The Archer makes a great target for astronomers

Hide your chips! The Seagull Nebula – also known as IC 2177 – is about 3650 light-years from Earth and is a relatively bright and very large emission nebula found between the constellations Monoceros and Canis Major. The Seagull Nebula has an apparent size about seven times that of the full moon. Photo: MPAS member Nik Axaris

In the August skies you can find Sagittarius, the Archer, lying almost overhead, and to its southwest 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.

Two interesting open clusters, M6 and M7, are nestled among rich star fields in Scorpius, and both are visible to the naked eye in an average dark-sky location.

In Sagittarius is M8, the Lagoon Nebula, which is visually about three times the size of the full moon and is the largest and brightest of several nebulosities in and around Sagittarius. It is an excellent target for a small telescope. And M17, the Omega Nebula, is also a good target for a small telescope. It is a glowing cloud of hydrogen gas that resembles the Greek capital letter ‘omega’.  Using a larger telescope with wide enough field of view you can also glimpse the Trifid Nebula, M20. Its name means ‘divided into three lobes’. M20 is an unusual combination of an open cluster of stars: an emission nebula, a reflection nebula and a dark nebula.

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.

Planet Mercury will be at its greatest elongation east on August 10, which means it is at its farthest distance from the sun, and then at its highest altitude in the evening sky on August 12. This month’s conjunctions, which is when two astronomical objects appear close to each other in the sky, include the moon and Saturn on August 3, the moon and Jupiter on August 8, then the moon and Saturn on August 31. On August 30-31, a blue moon will shine brightly in the night sky. A blue moon just means it is the second full moon in August. And no, it will not turn blue.

By Nerida Langcake
This article appeared in the August 2023 issue of the Mornington Peninsula Magazine.