Astronomy 2021: prime occasions for the approaching yr


Eclipses, meteor showers, eclipses and more are waiting for the next year of astronomy 2021.

Ready for another exciting year of sky watching? 2020 spawned several memorable astronomical events including a startling unaided comet C / 2020 F3 NEOWISE, the safe geminid meteors, and a one-off close pairing of Jupiter and Saturn that round off the year.

The sun also awoke from its slumber when solar cycle # 25 (finally) began in earnest, and the final half of 2020 produced some of the most massive sunspots in recent years. Expect more of this in 2021, along with increased aurora activity, as we near the height of the 11-year solar maximum in mid-2025.

A sunrise sunspot at the end of 2020 … more of that for 2021? Photo credit: Dave Dickinson

Top 10 astronomical events for 2021

First, here's a distilled list of the best of the best events for the coming year, in chronological order:

From January: mutual eclipse season for Jupiter's moons.

17th April: An occlusion of Mars by the moon.

May 26: A total lunar eclipse.

June 10th: An annular solar eclipse.

23rd June: Mars crosses the beehive (M44).

12. August: The peak of the Perseid meteors.

18th of August: A close connection between Mars and Mercury.

October 10th: Taurid fireball season tips.

November 19th: A partial lunar eclipse.

December 4th: A total solar eclipse.

So what can you look forward to in 2021? Here's our annual look at the top skywatching events popping up near you:

Eclipse Action in 2021

2021 contains the minimum number of eclipses that can occur in a calendar year of four: two solar and two lunar eclipses.

Lunar eclipse stages. Photo credit: Dave Dickinson.

Lunar eclipses include: A total lunar eclipse May 26with a maximum duration of 15 minutes in the Pacific region and a deep (97% umbral) partial lunar eclipse November 19ththin favor of the Americas, Northern Europe, East Asia, Australia and the Pacific.

The only total solar eclipse for 2021. Photo credit: NASA / GSFC / A.T. Sinclair.

Solar eclipses in 2021 include: an annular solar eclipse June 10ththwith a maximum duration of 3 minutes and 51 seconds when crossing the Arctic and a total solar eclipse December 4thwith a maximum duration of 1 minute and 54 seconds through the Antarctic.

The sun and moon in 2021

Both equinoxes mark the peak of the aurora season as well as the period of the geostationary satellite eclipse and the flare season, as distant satellites reach full illumination shortly before and after entering and exiting the earth's shadow. The equinox is also a great time to spy on the elusive zodiac lights in the morning or evening light. In contrast, the solstice marks a period when the International Space Station enters a period of full illumination, with June favoring the northern hemisphere for multiple sightings in one night and December favoring the southern.

Here are the seasonal start dates for 2021:

January 2nd: The earth is in perihelion

March, 20thth: Equinox to the north

June 21stst:: North Solstice

5th Julyth:: The earth is at aphelion

September 22nd: Equinox to the south

21st Decemberst: Solstice to the south

2021 continues to be an "ecliptic-like" year in terms of the path of the moon relative to the ecliptic plane as we move towards the "hilly years" in the middle of the decade around 2025. 2021 is the "supermoon" or the full moon at the next perigee (plus a total lunar eclipse) occurs on May 26th, and the "minimoon" with a full moon at the closest apogee occurs on 19. Decemberth. A blue moon also occurs on August 22ndnd, in the old contemporary archaic sense of the 3rd in a season with 4th

Coverages in 2021

It's always fun to watch the moon cover a bright star or planet as it weaves its monthly flight around the ecliptic plane. The moon will cover seven planets seven times in 2021: Mercury twice, Venus twice and Mars three times:

17th April: Mars versus 26% illuminated, growing crescent for Southeast Asia.

The moon covers Mars for Southeast Asia. Credit: Occult 4.2.

12th of May: Venus versus 1% illuminated, thinly growing crescent for the South Pacific.

November 3rd: Mercury against a 2% illuminated waning crescent in northeast North America.

November 8th: Venus versus 20% Illuminated Growing Crescent for the Northwest Pacific Region.

3rd of December: Mars versus a 1% illuminated waning crescent for Northeast Asia.

December 4th: Mercury versus 1% Illuminated Growing Crescent for South Africa.

DecEmbers 31st: Mars versus a 6% illuminated waning crescent for Southeast Asia.

The moon fails to occult a star of magnitude +1 in 2021, but visits Mebsuta (Epsilon Geminorum), Acrab (Beta Scorpii) of magnitude +2.6, Lambda Sagittarii of magnitude +2.8 and Sigma Sagittarii of magnitude in 2021 +2.1.

Highlighted events for eclipses of these stars in 2021 are:

Jan.uary 26thth: Epsilon Geminorum for Southeast Asia (96% illuminated, growing moon).

FebRuary 5th: Beta Scorpii for India (38% lit, waning crescent moon).

April 3approx: Lambda Sagittarii for Australia and Southeast Asia (60% illuminated, waning moon).

April 28th: Beta Scorpii for South Africa (97% illuminated, waning moon).

28th of Mayth: Sigma Sagittarii for North Africa and the Middle East (94% illuminated, waning gibbous moon).

June 24thth: Lambda Sagittarii for South Africa (99% illuminated moon at full moon).

25th Juneth: Sigma Sagittarii for North America (99% illuminated moon near full).

22nd of Julynd: Sigma Sagittarii for North Africa and Southwest Asia (91% illuminated, growing moon).

August 19thth: Sigma Sagittarii in southern North America (89% illuminated, growing moon).

SeptEmbers 2nd: Epsilon Geminorum for Europe (21% illuminated, waning crescent).

Occlusions: asteroids versus stars

Small asteroids can occasionally pass by in front of distant stars and briefly reveal their shape, while their "shadow" flits across the surface of the earth and over any diligent observer who happens to be watching on their way. Hundreds of asteroid occultations are predicted every year.

The brightest star hidden by an asteroid will appear in 2021 September 20ththAs a 762, Pulcova has a +7.1 star for Mexico and the southeastern United States.

The planets in 2021

The dance of the planets across the sky will continue in 2021. The worlds Mercury and Venus are inside the earth's orbit and always appear in the morning or evening sky and race back and forth around the sun. The best time to catch either world is when they are approaching their greatest extent or farthest from the Sun as seen from Earth.

The largest strains for Mercury and Venus in 2021 are:

January 23: Mercury is 19 degrees east of the sun at dusk.

6th March: Mercury is 27 degrees west of the sun at dawn.

17th of May: Mercury is 22 degrees east of the sun at dusk.

July 4th: Mercury is 22 degrees west of the sun at dawn.

September 14th: Mercury 27 degrees east of the sun at dusk.

October 25: Mercury is 18 degrees west of the sun at dawn.

October 29th: Venus is 47 degrees east of the sun at dusk.

Also look at Venus June 4ththwhen it passes 18 degrees east of the sun in front of the open cluster Messier 35 at dusk and continues to chase Mars over the beehive cluster (Messier 44) 3rd of Julyapprox26 degrees east of the sun at dusk. Mars continues to cross the M44 23rd Juneapprox in June 24thth.

Mars crosses the beehive cluster. Image credit: Stellarium.

Outer planets orbiting the sun outside of the earth can reach opposition and rise against the setting sun. This is the best time to observe any particular planet as it stays above the horizon all night. For most years, any of the outer planets can reach opposition. Only a fast Mars can alternately skip years … and 2021 is exactly such a year.

4th of Marchth: 4 Vesta reaches the opposition with + 6th magnitude in the constellation Leo.

July 17thth: Pluto reaches opposition at +14th magnitude in the constellation Sagittarius.

August 2nd: Saturn reaches an opposition in the constellation Capricorn with a strength of +0.2.

20th of Augustth: Jupiter reaches the opposition with a magnitude of -2.9 on the border between Capricorn and Aquarius.

September 14thth: Neptune reaches the opposition with a magnitude of +7.8 in the constellation Aquarius.

NovEmbers 4thth: Uranus reaches an opposition in the constellation Aries with a magnitude of +5.7.

November 27thth: 1 Ceres reaches an opposition with a strength of +7 in the constellation Taurus.

The reciprocal solar eclipse season for Jupiter's main moons begins in early 2021 when the four great Galilean moons pass each other, casting shadows and obscuring each other in their complex orbital dance. Innermost Io is actually accompanied by a "faux moon" 2nd of Aprilndwhen the star 44 Capricorni with a magnitude of +5.9 passes only about 0.5 inches from the moon at ~ 6:20 EDT / 10:20 UT.

Various transits and eclipses from Jupiter's moons. Photo credit: Dave Dickinson

Saturn's rings are 18 degrees open compared to our view in 2021, with the planet's north pole currently tilted towards the Sun, and that tilt narrows towards the edge in 2025.

The best connections in 2021

The "Great conjunction" of Jupiter and Saturn on December 21, 2020 was one for eternity. And hey, many planetary conjunctions happen every year that make dramatic celestial pairings as the clockwork solar system turns. We say "conjunction" when there is a pairing and "grouping" when there are three or more.

Some of the best heavenly meetings in 2021 are:

To damageCH 5th: Mercury-Jupiter 21 ’at dawn, 27 degrees from the sun.

March 10thth: Mercury, Jupiter, Saturn and the waning crescent form a 14 degree circle at dawn, 14 degrees from the Sun.

Looking east at dawn on the morning of March 10th. Image credit: Stellarium.

April 25th: Mercury-Venus are one degree apart at dusk, only seven degrees from the Sun.

12th of Mayth:: Venus and the slender growing crescent moon are only one degree apart at twilight, 12 degrees from the sun.

July 11th: Venus, Mars, and the growing crescent moon fit in a 3 degree circle, 29 degrees from the sun in the evening sky.

Look west on the evening of July 11th. Image credit: Stellarium.

July 30thth:: Mars regulus are 36 inches apart, 23 degrees east of the Sun in the evening sky.

August 18thth:: Mercury and Mars are 4 inches apart, 17 degrees east of the Sun in the evening sky. This is the best conjunction for 2021.

Comet at perihelion

Comets come and go every year. While most of the notable periodic comets follow known orbits, new comets may appear on orbits measured thousands or millions of years ago without warning. Will 2021 host a "Great Comet"? Nobody really knows … but for now, here is the list of certain known comet appearances to see for the year ahead:

May 26th:: Comet 7 / P Pons-Winnecke reaches perihelion and shines in the constellation Aquarius with a strength of +8.

July 13thth:: Comet 15P / Finlay reaches perihelion and shines in the constellation Taurus with a strength of + 9.

August 21st:: The comet 8P / Tuttle reaches the perihelion and shines in the constellation Cancer with a strength of +9.

17th of Septemberth: Comet 6P / d’Arrest reaches perihelion and lights up with Sagittarius with a power of +9.

November 3rdapprox: Comet 67 / P Churyumov-Gerasimenko reaches perihelion and shines in the constellation Gemini with a power of +9.

meteor S.howers in 2021

2021 is an “off year” for many large showers, including the Geminids, Leonids and Quadrantids, due to the disruptive moon phase. Your best choice in 2021 are the faithful August Perseids, where the growing crescent is sure not to be seen:

May 6th: The Eta-Aquariids peak at a Zenithal Hourly Rate (ZHR) of 50 during a 23% illuminated, waning crescent.

June 7th: The daytime arietids peak with a ZHR of 30 during a 7% illuminated, waning crescent.

August 12th: The Perseids peak with a ZHR of 100 during an 18% illuminated, growing crescent moon.

October 10th: The Tauriden peak with a ZHR of 10 during a 22% illuminated, growing crescent moon (note: the source comet 2P / Encke just reached perihelion in 2020).

DecEmbers 3approx: The Andromedids peak with a ZHR of 20 during a 1% illuminated, waning crescent.

We can look forward to this in the beautiful year of astronomy in 2021. Take a look at this section: we will write about these events and more in the year ahead.

Photo credit: Comet C / 2020 F3 NEOWISE over Kitt Peak. Photo credit and copyright: Robert Sparks.

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