December 2020 guide to bright planets | The basics of astronomy

Click on the name of a planet to learn more about its visibility in December 2020: Jupiter, Saturn, Mars, Venus, Mercury

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Jupiter and Saturn will be released first after dark in December 2020, and will continue to do so until the end of the year. Both of these worlds appear bright and beautiful after dark, despite being low in the southwestern sky. Day after day, the duo appear a little lower in the sky after dark and go to bed earlier after dark. To see these worlds, find a clear horizon towards sunset, and look for them low in the sky as soon as darkness falls.

All over the world, Jupiter and Saturn set about 3 1/3 hours after the sun in early December. Towards the end of the month, the duo follow the sun below the horizon approximately 1.5 hours after sunset.

For the first time since 2000, Jupiter and Saturn will have a great conjunction this year, on December 21, 2020. Great conjunctions of these two giant worlds occur every 20 years, but this year’s event will be the conjunction Nearest Jupiter-Saturn. since the year 1623. Astronomers use the word conjunction to describe the meeting of planets and other objects on the dome of our sky. They use the term great conjunction to describe a meeting of Jupiter and Saturn. The last great Jupiter-Saturn conjunction took place on May 28, 2000. The next will be on December 21, 2020. Watch for these worlds to come closer and closer during the first three weeks of December 2020.

Read more: Before the end of 2020, a great conjunction for Jupiter and Saturn

If you have a telescope, it is best to use it when Jupiter and Saturn are highest for the night at dusk / dusk. In other words, you have to catch them soon after sunset. Typically, the view of Jupiter’s four large moons and Saturn’s glorious rings through the telescope is sharper when these worlds are higher than they are below. The thickness of Earth’s atmosphere near the horizon tends to obscure the view of the moons of Jupiter and the rings of Saturn.

Jupiter’s moons positions via Sky & Telescope

Look first for the brilliant Jupiter; Saturn is the shining object immediately east of Jupiter for the first three weeks of December. Although Saturn is easily as bright as a first magnitude star – as bright as the brightest stars in our sky – the ringed planet cannot compete with the planet King Jupiter, which outshines Saturn by about 11 times. After all, Jupiter almost always ranks as the fourth brightest celestial object, after the sun, moon, and planet Venus, respectively (although Mars temporarily ruled as the fourth brightest celestial body – and Jupiter as the fifth. the brightest – in October 2020.).

Watch the moon around Jupiter and Saturn for a few days on December 16 and 17.

March lords over the southeastern sky as darkness falls in December in northern latitudes. From the southern hemisphere, Mars is seen high in the northern sky as night falls. Its fiery red splendor lights up the night long after midnight. In October 2020, Mars was brighter than it will be until September 2035. This is because – on October 13, 2020 – Mars reached opposition in our sky, while it was facing the sun seen from Earth. In opposition, the Earth sweeps between Mars and the sun. Now – in its smaller, faster orbit – Earth is now rushing forward, leaving Mars behind. So, in the coming months, Mars will slowly but surely darken in our night sky.

Even so, Mars remains bright and beautiful throughout December. Let the moon guide you to Mars for several nights centered on or around December 23.

Venus – the brightest planet – reached its maximum aspect ratio relative to the sun in the morning sky on August 12 or 13 (depending on your time zone). But the dazzling Venus will remain bright and beautiful as a morning “star” for the remainder of this year and for the first few months of 2021.

At northern mid-latitudes, Venus rises about 2.5 hours before the sun in early December, decreasing to about 1.5 hours at the end of the month.

At and near the equator, Venus rises 1 5/6 hours before the sun in early December, diminishing to 1 1/2 hours at the end of the month.

In temperate latitudes of the southern hemisphere, Venus rises just under an hour and a half before the sun throughout December.

Throughout December, Venus in its faster orbit around the sun will move further and further away from Earth. Seen through the telescope, the increasing gibbous phase of Venus will expand, but the overall size of its disk will decrease. The disk of Venus is illuminated at 89% at the beginning of December and at 94% at the end of the month; Venus’s angular diameter, on the other hand, will shrink to around 91% of its original size by the end of December.

Watch for the waning crescent moon that shines with Venus in the morning sky for several days, centered around December 12.

Mercury will not be easy to catch this month from all over the world. Mercury begins the month in the morning sky and ends the month in the evening sky. Look for this world in your western skies after sunset in January 2021.

What do we mean by a bright planet? By bright planet we mean any planet in the solar system which is easily visible without optical aid and which has been observed by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter, and Saturn. These planets actually appear bright in our sky. They are generally as bright – or brighter than – the brightest stars. Additionally, these relatively near worlds tend to shine with a more stable light than distant twinkling stars. You can spot them and get to know them as loyal friends if you try.

Conclusion: December 2020 presents three bright planets in the evening sky: Mars, Jupiter and Saturn, as well as the brightest planet of all in the morning sky: Venus. Jupiter and Saturn will have their conjunction once every 20 years on December 21.

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