The December 2021 Night Sky

The December 2021 Night Sky

Welcome to the December night sky. The dark cold nights of this month are ideal for observing the many meteor showers we have in December. I am aware of at least seven of them, starting on the 10th with the Monocerotids and the Chi Orionids.

On the 11th, we have the Sigma Hydrids, and the most important shower in December is the Geminids that occurs on the night of the 13th into the morning of the 14th. This event is well known for its high number of bright fireballs that leave a luminous smoke trail behind them.

Almost all periodic meteor showers come from dust originating in the tail of a comet, but the Geminids have their origins from an asteroid called 3200 Phaethon. The mechanism for getting dust from an asteroid usually involves a high-speed collision throwing off the dust and debris.

On the 16th, we have Piscids, on the 20th we have the Delta Arietids and, finally, on the 22nd, we have the Ursids.

This means that, on any dark clear night in December, we have an excellent chance of catching a falling star from practically any point in the sky.

There is a total solar eclipse on December 4, but this is only visible from the far southern hemisphere, principally Antarctica.

The brilliant planet Venus was at its highest point in the early evening sky at the end of November and, during the first week of December, it will be at its brightest. During the Christmas week, Venus will be seen low in the southwest and will be the brightest star-like object in the evening sky, appearing to us as a Christmas star.

The newly-discovered comet Leonard will be seen in the evening approximately from the 9th and this comet will be at its closest to Earth and possibly at its brightest on the 12th.

If this comet performs as it is expected to, it should be visible without telescope appearing low on the southwest horizon just after sunset. And it will be seen below the bright planet Venus on the evening of the 17th.

The Moon is new on the 4th, first quarter on the 11th, full on the 19th and last quarter on December 27.

By Clive Jackson
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Clive Jackson is the director of the Camera Obscura attraction (next to the Castle in Tavira), specialising in education and public outreach.
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To see the December Sky Map click on the pdf link below

Algarve Resident 2021-11-25 electronic edition