October: Magellanic Clouds take celestial centre stage

The Rho Ophiuchi cloud complex (pronounced ‘oh-fee-yoo-ki’ and named after a bright star in the region) is a dark, an emission and a reflection nebula about 14 light-years across. It is located some 460 light-years from Earth in the constellation Ophiuchus, the Serpent-bearer. It is one of the closest star-forming regions to the solar system. Photo: MPAS member Chris Kostokanellis

Two of the celestial showpieces of the southern skies are on show this month, the Large and Small Magellanic Clouds. These galaxies lie relatively close in space to the Milky Way. The irregular galaxy known as the Small Magellanic Cloud (SMC) sits in the constellation Tucana and can be seen with the unaided eye. It stretches roughly seven times the moon’s apparent diameter across the sky. The Large Magellanic Cloud (LMC) is also visible to the unaided eye and is a magnificent sight on the Dorado-Mensa border. Binoculars or small telescopes reveal many star clusters and patches of nebulosity within the LMC.

Also occurring is the annual Orionid Meteor Shower. Orionids are active every year in October, this year peaking on the night of October 21-22. At its peak there are potentially up to 15 meteors visible every hour. The Orionid meteor shower is the second annual meteor shower created by Halley’s Comet. No special equipment or a lot of skill is required to view a meteor shower. All you really need is a clear sky and lots of patience. For optimum viewing, find a secluded spot away from the city lights. Once you have found your viewing spot, make sure you are comfortable, especially if you plan to stay out long – meteor-watching can be a waiting game!

Mercury, the innermost planet in our solar system, will be at its highest altitude in the morning sky on October 8 and at dichotomy, which means that half of its Earth-facing side will be illuminated by the sun. Conjunctions this month include the moon and Saturn on October 6, the moon and Jupiter on October 9, and the moon and Mars on October 15.

October 23 sees Saturn end retrograde motion, then October 31 is when Mars will enter retrograde motion, which is an apparent change in the movement of the planet through the sky. It is not real, in that the planet does not physically start moving backwards in its orbit. It just appears to do so because of the relative positions of the planet and Earth and how they are moving around the sun.

By Nerida Langcake
This article appeared in the September 2022 issue of the Mornington Peninsula Magazine.