A new comet, two supermoons and starfalls: what to see in the sky in 2021

Nature provides us with many astronomical events that can only be seen once in a lifetime. In December 2021, we may have a chance to witness another one. We are talking about the first astronomical discovery in 2021 and other events observed in the night sky.

Comet C / 2021 A1 (Leonard)

The first comet that scientists have discovered in the new year, 2021, seems to be the year’s brightest comet. And its appearance is one of the most events for all astronomy lovers. Unfortunately, it will take a long time to wait for its appearance – it will fly as close to Earth as possible only in December. Scientists predict that its approach will make it possible to see it in the night sky with the naked eye. It is registered in the Minor Planet Center’s electronic circular under the name C / 2021 A1 (Leonard).

How was the comet discovered?

The first comet was detected on January 3 in images taken by the 1.5-meter reflector telescope of the Catalina Sky Survey in Arizona, USA. The new comet, designated C / 2021 A1 (Leonard), was discovered by H.J. Leonard at the Mount Lemmon Observatory in Arizona. Catalina Sky Survey (CSS) – The Catalina Sky Survey is a NASA-funded project supported by the Near-Earth Objects Observation (NEOO) Program of the Planetary Defense Coordinating Office (PDCO). The CSS mission is all about the detection and tracking of Near-Earth Objects (NEOs).

At the time of detection, the comet was located in the constellation Dogs Hounds and had a magnitude of about +19 magnitude. She has a gas-dust coma up to 10 arc seconds in diameter and a short dust tail up to 5 arc seconds long in the images. Recall that comets change rapidly when approaching the Sun: the volatile matter of comet nuclei begin to evaporate, they have a gas-dust atmosphere – a coma, and their tails “grow back.”

What is apparent magnitude?

Visible stellar magnitude (denoted by m) is a measure of the brightness of a celestial body (more precisely, the illumination created by this body) from the point of view of an earthly observer. Typically, a value is used to correct the value it would have in the absence of atmosphere. The brighter the object, the lower its magnitude.

The refinement “visible” indicates only that this stellar magnitude is observed from the Earth; this refinement is needed to distinguish it from the absolute stellar magnitude (which is a characteristic of the source itself and not its conditions observation). It does not indicate the visible range: values ​​measured in the infrared or any other range are also called visible. The quantity measured in the visible range is called visual.

In the visible part of the spectrum, the brightest star in the night sky is Sirius, which has an apparent magnitude of −1.46m. In the Northern Hemisphere’s middle latitudes, the comet will be available for amateur observations from September 2021. She will slowly move against the background of the constellations Ursa Major, Hounds Dogs, and Hair of Veronica.

Comet flight

On December 12, 2021, C / 2021 A1 (Leonard) is expected to be 0.233 astronomical units from Earth and seen with the naked eye. One astronomical unit is the distance from the earth to the sun and is equal to 149,597,870,700 meters.

However, this is not the only feature of the new comet. On December 18, 2021, C / 2021 A1 (Leonard) will fly 0.0283 astronomical units from Venus. C / 2021 A1 is notable because it will pass very close to Venus – only 4.2 million kilometers. In the entire history of astronomical observations, only five comets flew closer to Earth.

On January 3, 2022, it will pass its perihelion point at a distance of 0.61 astronomical units from the Sun. Recall that perihelion is the closest point of the orbit of a planet or another celestial body of the solar system to the sun. The antonym of perihelion is aphelion – the point of the orbit farthest from the Sun. The imaginary line between aphelion and perihelion is called the line of apses.

How to see a comet?

Scientists predict that the comet will reach a maximum brightness of about +4 magnitude as it approaches Earth. In fact, it may be even brighter. Because at this moment, C / 2021 A1 will be located between the Sun and the Earth, one can expect the effect of forwarding scattering and, as a consequence, high brightness of the dust tail. Considering the effect of forwarding scattering, the comet can reach a maximum brightness of about +1.5 magnitude.

However, from the end of November, the situation will change – the apparent angular velocity of the comet’s movement across the sky will increase significantly, and observers will have only a few days to see it near its maximum brightness. From 1 to 13 December 2021, C / 2021 A1 (Leonard) will move rapidly against the background of the constellations Bootes, Serpent, Hercules, and Ophiuchus, with dual visibility – morning and evening. Then it will move to the sky of the Southern Hemisphere.

This comet will be initially visible from the northern hemisphere and visible from the southern hemisphere in December 2021 and January 2022.

Lunar eclipses

A total lunar eclipse with a maximum phase of 1.01 will occur on May 26. It will coincide with the so-called supermoon, in which the full moon coincides with the moment of the closest approach of the Moon and the Earth. At such times, the Moon appears to observers on Earth about 14% larger and 30% brighter than usual.

The lunar eclipse will occur in the daytime for most of Russia and will be visible in the evening only in the Far East. The short full phase can be seen only in the Khabarovsk and Primorsky regions, in Kamchatka and Chukotka, and adjacent territories. A little further to the west, only decreasing partial phases of the eclipse can be seen.

The next time the Moon will hide from observers on November 19. In different phases, residents of the eastern half of the country will observe this eclipse. The phenomenon is best considered in the north of Russia, Kamchatka, and Chukotka. The eclipse will be almost total and will be observed in the evening hours.

Solar eclipses

Astronomers predict an annular eclipse of the Sun on June 10. Russians will be able to see both the ring-shaped and partial phases of this event. The solar disk will hide from the eyes of observers by 91.5%. Residents of the northeastern part of Russia will observe the annular solar eclipse on June 10. In most of the country, only partial phases of the eclipse will be visible, and the Far East will admire the solar ring around the Moon. The main phase will last 3 minutes, 51 seconds, and the entire cycle will take about two hours.

On December 4, a total solar eclipse will occur, which will be visible from the Pacific and Atlantic oceans and Antarctica. Partial phases of the eclipse will be observed in southern Africa and southern Australia. The eclipse will not be visible from the territory of Russia.


The brightest asteroid in the night sky will be the asteroid, Vesta. In 2021, it can be observed on March 4. Obviously, observations are possible only if the sky is clear, and the weather is good. Then the asteroid can easily be seen with the naked eye. You can see Vesta in the region of the constellation Leo. On March 4, the brightness of the asteroid will reach its maximum value.

Super Moon

Supermoon is a phenomenon when the full moon coincides with the moment of the Moon’s closest approach to the Earth. With a supermoon, the moon looks larger and brighter than on normal days. Russians will be able to see this unusual phenomenon on April 27 at around 6 am. The Moon in this phase looks most impressively above the horizon.

Generally speaking, a supermoon is a full moon that appears larger than the typical full moon due to being closer to Earth.

However, this is not all. In fact, there are several definitions of “supermoon.” Consider two of the most popular definitions, which we will call “general” and “strict” definitions:

  • General definition: A supermoon is a new or full moon that occurs at about the same time as perigee (the point in the moon’s orbit where it is closest to Earth). By this definition, there can be several supermoons in a year.
  • A strict definition: a supermoon is the next nearest new moon and full moon of the year. According to this definition, there can only be two supermoons per year (supermoon at full moon and supermoon at new moon).
    In popular use, most people adhere to a broad definition since it is much more interesting to be able to talk about several supermoons rather than one or two.

Another measure used to determine if the full moon is a supermoon is its physical distance from Earth. The exact distance limit varies, but we tend to stick with the idea that a full moon that occurs closer than 360,000 km is considered a supermoon.

How many supermoons will there be in 2021?

Based on the broad definition of this term, in 2021, there will be two supermoons in the sky.

The first full moon will be available for review on April 26 and 357 615 km from Earth.

The second full moon will be available for review on May 26 and will be located at a distance of 357,462 km from Earth.

The Full Moon in May is especially notable for two reasons:

The moon will be closest to Earth in 2021 during this period.
In some areas, this coincides with a total lunar eclipse, which means that it will take on a reddish tint during the maximum eclipse. In other words, it will be a “blood moon.”
Unfortunately, the eclipse will only be visible in some parts of the world.

Why do supermoons appear in the sky?

It all comes down to the fact that the Moon’s orbit around the Earth is not a perfect circle – in fact, it is an elliptical (oval) shape.

Because of this, the distance of the moon from the earth changes as it moves around our planet. The Earth is not directly in the middle of this elliptical orbit, so there are points in the Moon’s orbit where it is closest and farthest from Earth. These points are called perigee and apogee, respectively.

Perigee is the point in the Moon’s orbit that is closest to Earth.
Apogee is the point in the Moon’s orbit farthest from Earth.
The moon makes one complete revolution around the Earth in about 29.53 days, which means that it reaches its perigee and apogee points about once a month. When this occurs simultaneously as the full moon, it is called the syzygy of perigee, or more commonly, the supermoon.

“Syzygy” is an astronomical term for the coincidence of three or more celestial bodies (such as the Sun, Moon, and Earth). When the Sun, Earth, and Moon form a syzygy, we experience a full moon or a new moon, depending on whether the moon is between the sun and the earth or the earth is between the sun and the moon.

Where did the term “supermoon” come from?

Although it has been all over the news in recent years, “supermoon” is not an official astronomical term. In fact, it didn’t even exist until astrologer Richard Nolle invented it in 1979.

At the time, Nolle defined the supermoon as “a new moon or full moon that occurs when the moon approaches the Earth in or near (within 90%) of a given orbit.” This definition is what most people hold today, although we only pay attention to full moons, super moons because they are much more interesting to watch!

Does the supermoon really look bigger?

Given that the full moon in a supermoon is closer to Earth than a normal full moon, it does appear larger – about 7% larger, technically speaking. This means that the difference between a full moon at perigee and a full moon at apogee can be up to 14%, which is significant.

However, here’s the key fact: If you somehow can’t compare a normal full moon and a supermoon side by side in the sky, it’s almost impossible to sense a 7% difference in moon size.

Even if you could somehow place the largest possible moon of the year (full moon at perigee) next to the smallest (full moon at apogee) in the sky, you would hardly notice the difference. And this is with absolute extreme moons!

The bottom line is that it is difficult to truly sense any difference in the moon’s size from month to month or from night tonight, so don’t expect to see a giant moon there.

The moon near the horizon will always look huge due to a well-known phenomenon called the Moon Illusion, which causes our minds to exaggerate the size of objects near the horizon.

Meteor showers
May 3-7. Meteor shower eta-Aquarids or “May meteor shower.”

A moderate-strength meteor shower associated with Halley’s comet. It takes place annually from the end of April to the end of May. In 2021 the peak of activity is predicted for May 6-7. In the Northern Hemisphere, up to 70 meteors per hour can be seen in the sky. It is best to observe the phenomenon away from city lights in the morning hours.

The meteor shower is active from April 19 to May 28 of each year. Named after the constellation Aquarius. The fact is that the radiant, the point in the sky from which Eta Aquarids seems to emerge, is in the constellation Aquarius’s direction. The shower is named after the brightest star, Eta Aquarius. This Aquarius, 62 Aquarius, HD 213998 is a solitary star in the constellation Aquarius, approximately 168 light-years from the Sun. The apparent magnitude of the star is + 4.03ᵐ.

Eta-Aquarids is one of two meteor showers created by the debris of Halley’s comet. The Earth follows Halley’s path around the Sun for the second time in October. This creates the Orionids meteor shower, which peaks on October 20.

Halley’s comet takes about 76 years to complete a revolution around the Sun. The next time it can be seen from Earth in 2061.

August 10-20. Perseid meteor shower

The Perseid meteor shower is perhaps the most beloved meteor shower of the year in the Northern Hemisphere. It is a heavy meteor shower and is persistent. These fast and bright meteors emanate from a point in the constellation of Perseus the hero. As with all emission points in a meteor shower, you do not need to know Perseus to observe the shower; instead, meteors appear in all parts of the sky. These meteors often leave stubborn plumes. Perseid meteors tend to increase as late-night turns to midnight, and usually, most meteors form in the hours before dawn. In 2021, the growing crescent. Sets early evening, providing dark skies for this year’s Perseid meteor shower. The projected peak in 2021: the night of August 11-12.

One of the best for observing the 2021 meteor showers. The Perseids are particles of Comet Swift-Tuttle that can be seen in the constellation Perseus. The waxing moon will not hurt to consider the snow-white tails of meteors sharply tracing the sky. The peak of the meteor shower will come on the night of August 12-13. It will be possible to observe the space phenomenon after 22:00 and until the morning.

October 6-10. Draconid Meteor Shower

Draconids are associated with comet Giacobini-Zinner and are visible near the constellation Draco. This is a meteor shower with variable activity – in different years, it can vary from tens to thousands of meteors per hour. In 2021, the peak of activity will come on the night of October 8-9. Like other meteor showers, Draconids are best seen away from city lights.

December 4-17. Starfall Geminids

Unlike other meteor showers, the Geminids are not associated with a comet – the star rain is caused by the debris of the asteroid Phaeton 3200. In 2021, Russians will be able to observe the peak of the meteor shower on the night of December 13-14. The thin crescent moon of the growing moon will not overshadow the magnificent sight and will allow you to see every snow-white flourish in the sky. Falling stars can be seen worldwide, but most of the meteors will appear near the constellation Gemini.

How to observe stellar streams?

No special equipment or a lot of skill is required to view the meteor shower. While all you really need is clear skies, a lot of patience, and our handy interactive meteor shower sky map with a visibility meter to see the meteor shower, the following tips can help you get the most out of your shooting experience. Find a secluded viewing spot away from city lights. Once in place, it can take 15 to 20 minutes for your eyes to adjust to the dark. Dress for the weather and make sure you are comfortable, especially if you plan on staying away for a long time. Bring a blanket or comfy chair with you – watching meteorites can be a surprise game. Once you find your vantage point, lie on the ground, and look up towards the radiation source. Use our interactive meteor shower sky map or the table above to find the radiant’s current direction in the sky.

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Alexandr Ivanov earned his Licentiate Engineer in Systems and Computer Engineering from the Free International University of Moldova. Since 2013, Alexandr has been working as a freelance web programmer.
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Alexandr Ivanov

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