Comet C/2021 A1 (Leonard)
The first comet discovered by scientists in the new year, 2021, seems to bethe brightest comet
How was the comet discovered?
The first comet of the year was detected on January 3 in images taken by the 1.5-meter Catalina Sky Survey in Arizona, USA. The new comet, designated C/2021 A1 (Leonard), was discovered by G. J. Leonard at the Mount Lemmon Observatory in Arizona. Catalina Sky Survey (CSS)is a project funded by NASA and supported by the Near-Earth Object Observation Program (NEOO) under the Planetary Defense Coordination Office (PDCO).The CSS mission is entirely dedicated to detecting and tracking near-Earth objects (NEOs).
By Filipp Romanov (Philip Romanov) - Own work, CC BY 3.0
At the time of discovery, the comet was located in the constellation Canes Canes and had a magnitude of about 19 magnitude.In the images, it has a gas and dust coma with a diameter of up to 10 arc seconds and a short dust tailRecall that comets change rapidly as they approach the Sun: volatile substances of nucleiComets begin to evaporate, they develop a gas-and-dust atmosphere – a coma, and "grow back" tails.
What is apparent magnitude?
Apparent magnitude (denoted by m) - measurebrightness 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 that is corrected to the value it would have in the absence of atmosphere. The brighter the object, the lower its magnitude.
The qualifier "visible" only indicates thatthis 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 the conditions of its 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 atin the night sky - Sirius, which has an apparent magnitude of −1.46m. At the middle latitudes of the Northern Hemisphere, 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
12 December 2021 C / 2021 A1 is expected to(Leonard) will be 0.233 astronomical units from Earth and can be 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 byat 0.0283 astronomical units from Venus. C/2021 A1 is notable for the fact that it will passvery close to Venus, only 4.2 million kilometers away.In the entire history of astronomical observations, only five comets have come closer to Earth.
Location of comet C / 2021 A1 (Leonard) 10December 2021. By then it will be brighter, but closer to the horizon. As seen from the US about 30 minutes before sunrise. Illustration by Eddie Irizarri using Stellarium.
On January 3, 2022, it will pass its perihelion point at a distance of 0.61 astronomical units fromRecall that perihelion is the closest point to the Sun in the orbit of a planet or other celestial body in the Solar System.The antonym of perihelion is aphelion, the farthest point of the orbit from the Sun.The imaginary line between aphelion and perihelion is called the apse line.
This perspective of Comet C / 2021 A1 (Leonard) shows that in its trajectory it will be visible first from the northern hemisphere and then from the southern. Image courtesy of NASA / JPL.
How to see a comet?
Scientists predict that during its close approach to Earth, the comet will reach a maximum brightness of about 4 magnitude.In fact , it may turn out to be even brighter.Moment C/2021 A1 will be located between the Sun and the Earth, the effect of direct scattering and , as a result, the high brightness of the dust tail can be expected.Taking into account the effect of direct scattering, the comet can achieve 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 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 initially be visible from the northern hemisphere and will become visible from the southern hemisphere in December 2021 and January 2022.
Lunar eclipses
Total lunar eclipse with a maximum phase of 1.01will happen on May 26th. 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 during the daytimemost of Russia and will be visible in the evening only in the Far East. The short full phase can be visible only in the Khabarovsk and Primorsky territories, Kamchatka and Chukotka, and adjacent territories. A little further to the west, only the waning partial phases of the eclipse will be visible.
Next time the moon will hide from observers 19November. In different phases, residents of the eastern half of the country will be able to observe this eclipse. It is best to consider the phenomenon 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 eclipseSun June 10th. Russians will be able to see both the annular and private phases of this event. The solar disk will be hidden from the eyes of observers by 91.5%. Residents of the northeastern part of Russia will be able to observe an 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 be able to 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.
The fourth of December will be full solaran eclipse that will be visible from the Pacific and Atlantic oceans, as well as in 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.
Asteroids
The brightest asteroid in the night sky will beasteroid Vesta. In 2021, it can be observed on March 4. Of course, observations are only possible if the sky is clear and the weather is suitable. Then the asteroid can be easily seen with the naked eye. Vesta can be seen in the area of the constellation Leo. On March 4, the asteroid's brightness will reach its maximum value.
Super Moon
Supermoon - a phenomenon when the full moon coincideswith the moment of maximum approach of the Moon 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,supermoonis a full moon that appears larger than a typical full moon due to the fact that it is 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.
- Strict definition:the 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 parlance, most people stick to a broad definition, since it is much more interesting to be able to talk about several supermoons rather than just one or two.
Another measure that is used todetermining whether a 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, there will be two supermoons in the sky in 2021.
The first full moon will be visible on April 26 and will be at a distance of 357,615 km from Earth
The second full moon will be visible on May 26 and will be 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 it will take on a reddish hue during the eclipse's maximum. 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 changesas it moves around our planet. Also, 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 full revolution around the Earthin about 29.53 days, which means it reaches perigee and apogee about once a month. When this occurs at the same time as the full moon, it is calledsyzygyperigeeor, more often,supermoon.
"Syzygy" is an astronomical termdenoting 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 in recent years this has been said in allnews reports, "supermoon" is not an official astronomical term. In fact, it didn't even exist until astrologer Richard Nolle invented it in 1979.
At that time, Nolle defined the supermoon as“a new moon or full moon that occurs as the Moon approaches the Earth at or near (within 90%) a given orbit.” This definition — something that most people adhere to today, although we tend to only pay attention to full moons, super moons, as they are much more interesting to look at!
Does the supermoon really look bigger?
Considering that the full moon is in the supermoonCloser to Earth than a normal full moon, it actually appears larger — about 7% more, technically speaking. This means that the difference between a full moon at perigee and a full moon at apogee can be as much as 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 fit the mostthe largest possible moon in 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 size of the moon from month to month or night to night, 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"
Medium meteor shower associated with a cometHalley. 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.
Meteor shower is active from April 19 to May 28every year. Named after the constellation Aquarius. The fact is that the radiant, the point in the sky from which the Eta Aquarids appear to emerge, is in the direction of the constellation Aquarius. The shower is named after the brightest star, Eta Aquarii. Eta Aquarii, 62 Aquarius, HD 213998 is a single 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 showerscreated 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 my favoritemeteor shower of the year in the Northern Hemisphere. It's a massive meteor shower, and it's persistent. These fast and bright meteors originate from a point in the constellation of Perseus the Hero. As with all meteor shower emission points, you don't need to know Perseus to watch the shower; instead, meteors appear in all parts of the sky. These meteors often leave persistent trails. The number of Perseid meteors tends to increase as late night turns into midnight, and the most meteors are usually produced in the predawn hours before dawn. 2021 has a waxing crescent moon. Sets in the early evening, providing dark skies for this year's Perseid meteor shower. Predicted peak in 2021: the night of August 11-12.
One of the best meteor showers to watch2021. The Perseids are particles of comet Swift-Tuttle that can be seen in the area of the constellation Perseus. The waxing moon will not prevent you from seeing the snow-white tails of meteors sharply streaking the sky. The peak activity of the meteor shower will occur on the night of August 12-13. It will be possible to observe the cosmic phenomenon after 22:00 until the morning.
October 6-10. Draconid Meteor Shower
The Draconids are associated with Comet Giacobini-Zinner andvisible 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 occur on the night of October 8-9. Like other meteor showers, the Draconids are better visible away from city lights.
December 4-17. Starfall Geminids
Unlike other meteor showers, the Geminidsconnected not with a comet - the star rain is caused by the debris of the asteroid Phaethon 3200. In 2021, the Russians will be able to observe the peak of the meteor shower on the night of December 13-14. The thin crescent of the growing moon will not overshadow the splendid spectacle and will allow you to see every snow-white flourish in the sky. Falling stars can be seen all over the sky, but most of the meteors will appear near the constellation Gemini.
How to observe stellar streams?
No need to watch the meteor showerspecial equipment or a large number of skills. While all you really need is clear skies, a lot of patience, and our handy interactive meteor shower sky map with 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 appropriately 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 current direction of the radiant in the sky.
Helpful Resources for Observing the Night Sky
The best stargazing spots on EarthSky can be viewed here.
Find a spot in the dark sky from the International Dark Sky Association here.
Heavens-Above: satellite forecasts tailored to your location
Stellarium Online: star maps adapted to your location
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