Comet Leonard is racing towards earth – can it be seen with the naked eye?

Comet Leonard (C / 2021 A1) is approaching Earth at great speed and could soon be visible to the naked eye. What you need to know about observation.

Update from Friday, December 3rd, 2021, 9 a.m .: In astronomy, the saying “Comets are like cats: they have a tail and do what they want” applies. It refers to the fact that it is difficult to predict the brightness of a comet. So far, however, Comet Leonard (C / 2021 A1) has stuck to the predictions to some extent and can already be seen in binoculars or a small telescope. By its closest approach to Earth on December 12th, it could reach magnitude 4 and then possibly be seen with the naked eye in a dark sky. However, Comet Leonard is unlikely to be as bright and impressive as the summer comet Neowise in 2020.

If you want to watch Comet Leonard in the sky, you have to get up early. Currently, the comet rises in the east around 2 a.m. and rises there in the sky. If you want to observe it, you should wait until Leonard has climbed out of the haze near the horizon – it is particularly recommended to observe it before the sun rises, as the comet is then as high up in the sky as possible and can be easily seen. Comet Leonard (C / 2021 A1) is currently located near the conspicuous star Arctur in the constellation Bear Guardian.

Comet Leonard is moving fast: At a speed of 254,412 kilometers per hour it is currently racing towards Earth – but there is no danger: When it comes closest to Earth, on December 12, 2021, there is a distance between Comet Leonard and the blue planet of 34.4 million kilometers.

Comet Leonard (C / 2021 A1) is approaching the Sun and Earth

Update from Tuesday, November 30th, 2021, 4.15 p.m .: Comet Leonard (C / 2021 A1) is currently approaching the Sun ever closer; on January 3, 2022 it reached its perihelion, the closest distance to the Sun. Before that, it should be more noticeable in the sky. It currently has a magnitude of 7, so it can be observed with binoculars or a small telescope when the sky is clear. The comet is currently in the constellation “Haar der Berenike” and is on its way towards the constellations “Hunting Dogs”, “Bear Guardians”, “Snake” and “Snake Bearers”. On December 12th, it reached its closest position on earth – about 34.4 million kilometers away.

How the comet develops in the near future will determine whether it is visible to the naked eye in the sky. Lately it has developed well, its brightness has increased by several magnitudes. In pictures you can see that it has a green core and a delicate tail. Experts assume that Comet Leonard can reach magnitude 4 – then it would be visible in the sky with the naked eye.

Comet Leonard (C / 2021 A1) has already become significantly brighter

Update from Friday, November 26th, 2021, 8.40 p.m .: Comet Leonard (C / 2021 A1) continues its orbits across the night sky and has become significantly brighter compared to the beginning of November. It is now estimated by observers to have a magnitude of between 7 and 8 – that is, it can be spotted in the sky with binoculars or a small telescope. Comet Leonard is currently in the region of the constellation “Haar der Berenike” and the galaxy NGC4656 and is moving in the direction of the constellation “Bear Guardian”. On December 6th, Comet Leonard is near the conspicuous star Arctur, so it’s easy to find.

If you want to observe Comet Leonard, you have to be prepared to stay awake for a long time or to get up early: The comet does not rise in the northwest until midnight and rises in the sky during the course of the night. Even if Comet Leonard is called “Christmas Comet” by some, this name is misleading: The comet will reach its closest point to the Sun on December 12th (the so-called perihelion) and will then be very low in the sky when observed from the northern hemisphere. The best observation period is actually before December 12, 2021.

Comet Leonard: Not a “Christmas comet”, but possibly a heavenly spectacle

First report from Sunday, November 7th, 2021, 8:22 p.m .: Frankfurt – A comet that can be seen in the sky with the naked eye does not occur often. In recent years there has only been one comet that halfway falls into this category: Comet Neowise (C / 2020 F3) was visible to the naked eye for some time in the summer of 2020 and under very dark skies. But there could soon be a successor: Comet Leonard (C / 2021 A1) is currently being watched closely by astronomers – it has the potential to become bright enough. But you shouldn’t rejoice too soon – because the behavior of comets is very difficult to assess.

Comet Leonard was the first comet to be discovered in 2021: it was first spotted on January 3, 2021 by astronomer Greg J. Leonard at the Mount Lemmon Observatory in Tucson, Arizona. At that time, the comet was about 750 million kilometers from the sun. On January 3, 2022, its trajectory will be closest to the Sun, known as perihelion.

Leonard is then about 92.2 million kilometers from the sun. It already has its closest approach to Earth before that: The US space agency NASA estimates that Comet Leonard will come closest to Earth on December 12, 2021 at around 2:54 p.m. German time – at a safe distance of almost 35 million kilometers.

Comet Leonard (C / 2021 A1) could be visible to the naked eye in November / December 2021

How bright Comet Leonard will be in November and December 2021 will only show with time. According to estimates by the “EarthSky” portal, a brightness between magnitude 5 and 2.6 is assumed. The lower this value, the brighter the object can be seen.

But the behavior of comets is generally considered to be unpredictable, which makes it very difficult to predict how the brightness of Comet Leonard will develop. The comet Atlas, for example, was considered a bearer of hope in 2020 – and broke up before it could put on a show in the sky. Something similar happened to Comet Ison in 2013, which shattered on its closest approach to the Sun.

How to find Comet Leonard in the night sky

Should Comet Leonard become visible to the naked eye, it will first be seen in the northern hemisphere, and later in the southern hemisphere. The comet is traveling at a speed of 254,412 kilometers per hour – but you will not see it “racing” across the sky, as Leonard is very far from Earth.

One thing is certain: if you want to see the comet in the sky, you have to look out for it early in the morning. Around the middle of November, Comet Leonard wanders into the constellation “Haar der Berenike”, which rises around 1.30 in the east. On December 2nd, the comet can be seen very close to the globular cluster M3, and then moves on towards the bright star Arctur in the constellation “Bear Guardian”.

Comet Leonard could be seen with telescopes as early as mid-November

The specialist magazine “Sky & Telescope” estimates that the comet could reach a magnitude of 10 in mid-November – a brightness that cannot yet be seen with the naked eye, but can already be seen with smaller telescopes. Around the time that Comet Leonard is near the star Arcturus, it could reach a magnitude of 5.5 and thus become an object that can be faintly perceived with the naked eye.

In the northern hemisphere, you can catch the last glimpse of the comet in the morning sky on December 12, 2021 – shortly before its theoretically greatest brightness. It will then be visible deep in the southwestern sky at dusk. Observers in the southern hemisphere now also have the opportunity to take a look at the comet.

Comets are “dirty snowballs” from the depths of space

Comets come from the depths of space and consist of dust and rock that is held together by ice. When a comet gets closer to the sun, the ice melts and dust and stones are released – the characteristic comet’s tail is created. This is exactly what makes predicting the brightness of Comet Leonard (C / 2021 A1) so difficult: Nobody can predict exactly how the comet will behave in the rising heat – it will become more active, but how active? Nobody can reliably predict that at the moment.

Comets – nickname: “Cosmic Snowballs” – are of particular interest for research because they are considered to be messengers from the depths of the universe. According to NASA calculations, Comet Leonard comes from the outer solar system and has been moving over 550 billion kilometers towards the center of the solar system for 40,000 years. After he has reached his perihelion, according to NASA, he will probably be thrown out of the solar system. So winter 2021/2022 is the last chance to see Comet Leonard.

Only recently, two researchers accidentally discovered the largest comet known to date. It is on the way towards the center of the solar system, in 2031 it should reach its point closest to the sun. (Tanja Banner)

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