December offers us magnificent opportunities to observe our neighbors of the Solar System. Venus, Saturn and Jupiter shine splendidly in the sunsets, while Mars begins to be seen at dawn. Two rains of stars will also contribute to animate the December skies.
As we approach the winter solstice, the nights become more and longer, thus offering us more opportunities for the observation of the night sky. Venus, Saturn and Jupiter are visible from sunset and are upcoming in heaven, so they will form beautiful conjunctions.
The best time to observe them simultaneously is when something more than an hour has passed after sunset, that is, at about 7:00 pm - 19h30m (peninsular time). For the southwest we can observe the splendid Fulgor of Venus and, heading to the south and above, Saturn's discreet orange glitter and the most intense Jupiter. On December 6, the Moon will come to join the planetary trio appearing very close to Venus. The growing fourth fourth will be close to Saturn (day 7)
and then to Jupiter (days 8 and 9). We will then have the opportunity to observe four bodies of the solar system in a small region of the celestial vault.
After twilight, according to the night progress, Jupiter and Saturn will lose height, and every day they will be a little lower. At the end of December, Saturn will only be visible for an hour after sunset, for the southwest.
Although Venus, Jupiter and Saturn show us as close in heaven, remember that they are at very different distances from Earth. The distance to Venus is now of only 58 million kilometers (39% of the soil-sun distance), which is why it appears so extremely bright. The distances to Jupiter and Saturn are 780 and 1575 million kilometers, respectively; That is, Saturn is twice as far as Jupiter and 27 times farther than Venus.
Its different distances, sizes and atmospheric compositions, make the three bodies show very different brights. Venus is now 12 times brighter than Jupiter and 170 times brighter than Saturn.
The morning star of these days is Mars that, compared to the splendid evening lucefers, shines very modestly. It is half bright than Saturn and almost 400 times less bright than Venus.
However, it is exciting to verify as Mars goes back little by little to our skies. Now it is still far from Earth, about 370 million kilometers (much beyond the sun). But, in the coming months, the red planet will go approaching us and, according to all the constellations of the zodiac, will form beautiful conjunctions with the other planets: with Venus in February, with Saturn in April and with Jupiter in May. Thus, touring the zodiacal band, it will progress by the firmament, until its opposition with the Sun, the optimum moment for its observation, which will take place on December 8, 2022 when, in addition, it will be hidden by the Moon.
Mercury will peel timidly by the west horizon, after sunset, in the last days of the month. As usual, due to its weak brightness and its low elevation will be difficult to observe, but to locate it we can guide you for its proximity to Venus.
In December, two rains of important stars happen. Gemínidas take place between 4 and 17 reaching its maximum activity on the night of 13 to 14. However, the moon already very grown (the plenilunium will take place on day 19) shield the traces of the meteors during a good part of the evening. We will have to wait for at that 4h in the morning, when Selene has slept, to enjoy a dark sky.
After the gemnids, they make their urse (which have their radiant in the major bear, where their name comes from). The maximum activity of this rain of stars will take place on the night of 22 to 23, when the Moon will be routing, but still very illuminated. Therefore, this time it will be preferable to search meteors in the first part of the night, before the lunar ortho.
During these long nights, let's look for a while to direct our gaze towards the immense skies. It will be much better if we can do it away from the light pollution, which now shoots irresponsibly to stimulate the consumerous outflow of the Christmas campaign. The planets, the stellar profusion, the Milky Way and other wonders after the transparent winter skies, these are the true lights, which produce deep sensations and make us reflect on our presence in the world and about our way of life.
Rafael Bachiller is Director of the National Astronomical Observatory (National Geographic Institute) and academic of the Royal Academy of Doctors of Spain.
Date Of Update: 07 December 2021, 07:10
