Welcome to the December night sky. This is the month of the winter solstice in the northern hemisphere. This year, it is on December 21, and it happens when the Sun is at its lowest point in the sky, causing the shortest days and the longest nights of the year. In fact, if you travel north of the Artic Circle, the Sun fails to rise this time of the year.
The night sky is long and dark in December and, passing overhead currently, we have the winter Milky-Way. On the southern horizon, we have the long constellation of Eridanus the River. This constellation is towards the lower part of Orion the Hunter and below Taurus the Bull and Cetus the Whale.
In the winter Milky-Way, we have many bright stars including Capella in Auriga and Aldebaran in Taurus. Also, we have Rigel and Betelgeuse in Orion. Towards the east, and still in the winter Milky-Way, we have Procyon in Canis Minor and the brightest star in the nighttime sky that is Sirius in Canis Major “The Big Dog”.
The elusive planet Mercury passes between us and the Sun on the 6th and then it moves quickly away from the Sun to become a morning star visible low on the eastern horizon, rising two hours before the Sun by the 24th.
Venus is still an evening object in the direction south southwest. By the end of the year, it sets four hours after the Sun, so it will be visible in a dark sky and no doubt be mistaken for the Christmas Star this December.
The red planet Mars is in the constellation Cancer the Crab, and it can be seen rising over in the east as darkness falls. The Moon will pass in front of Mars as seen from Earth in day light hours at 09:00 in the morning of the 18th.
The gas giant planet Jupiter is at opposition on the 7th in the constellation of Taurus, near the star cluster of the Hyades. When a planet is at opposition, it rises at the east at sunset and is due south at local midnight.
The ringed planet Saturn is in Aquarius and sets soon after the Sun in December. This planet passes behind the Moon on the 8th, but this is not visible from Europe. On March 23, 2025, the Earth passes through the ring plane of Saturn; this means the rings are not visible from Earth for a few days.
The planet Uranus has passed opposition now and is near Jupiter at the moment and close to the star cluster of the Pleiades, but this planet is not easy to see normally, requiring binoculars.
The best meteor shower in December is the Geminids on the 14th of the month. This meteor shower is from an asteroid, 3200 Phaethon. This is unusual as meteors are normally from the tails of comets.
The Moon is new on the 1st, first quarter on the 8th, full on the 15th, last quarter on the 22nd and new again on December 30.
By Clive Jackson
|| features@algarveresident.com
Clive Jackson is the director of the Camera Obscura – Tavira EYE attraction, located near the Castle of Tavira. Specialising in education and public outreach.
281 322 527 | info@torredetavira.com www.torredetavira.com
To see the December Sky Map, click on the pdf link below
