During December, the constellations Taurus, Gemini, Orion, and Auriga are visible. Looking towards the north you can spot the distinct upside-down ‘V’ shape of the Hyades open star cluster, which marks the head of Taurus. Within Taurus you can also observe the open star cluster Pleiades, or M45, which can be seen with the unaided eye and is a wonderful sight in a small telescope.
Just next to it towards the northeast is Orion, a magnificent sight with its bright stars Rigel and Betelgeuse and the fantastic nebula M42. Emerging from the foot of Orion, Eridanus meanders high across the sky. Look out for Perseus and Auriga below Taurus in the north. Auriga can be found by locating the bright star Capella, which is low in the sky this month. December is also a great time to look out for the Magellanic Clouds in the south.
This month we also have the Geminids meteor shower – considered to be one of the most spectacular meteor showers of the year – on the night of December 13-14, with peak viewing time around 3am. The shower owes its name to the constellation Gemini because the meteors seem to emerge from this constellation. Unlike most other meteor showers, the Geminids is not associated with a comet but with an asteroid called 3200 Phaethon. As Earth passes through a massive trail of dusty debris shed by the weird, rocky object, the dust and grit burn up as they run into Earth’s atmosphere in a flurry of shooting stars. The asteroid takes about 1.4 years to orbit the sun.
On December 21 the Earth is at solstice, which is when the axis is tilted most closely towards the sun and the southern hemisphere sees its longest day. Also, if you look up from December 23-30 you will see four bright planets – Mercury, Venus, Saturn and Jupiter – all lined up in the evening twilight.
By Nerida Langcake
This article appeared in the December 2021 issue of the Mornington Peninsula Magazine.