Saturday, Dec. 4, Total Solar Eclipse Closes 2021 Eclipse Quartet

Summary: The Saturday, Dec. 4, total solar eclipse closes the 2021 eclipse quartet as the second of the year's two solar eclipses.

Saturday, Dec. 4, 2021, total solar eclipse details: "Permission is freely granted to reproduce this data when accompanied by an acknowledgment: Eclipse Predictions by Fred Espenak, NASA's GSFC," via NASA Eclipse Web Site

The Saturday, Dec. 4, total solar eclipse closes the 2021 eclipse quartet of two lunar eclipses and two solar eclipses as the second and last of the year's two solar eclipses.

December's solar eclipse is exclusively a southernmost Southern Hemisphere event. The path of totality for December's solar eclipse focuses continentally on West Antarctica and oceanically on the Southern Ocean, also known as the Antarctica Ocean or the Austral Ocean, and the southwesternmost reach of the South Atlantic Ocean.

The eclipse's path of partiality expands the event's visibility across the rest of Antarctica, known as East Antarctica or Greater Antarctica. The partial eclipse portion's northern limits visit the the south and subantarctic regions of the Atlantic Ocean and the Indian Ocean; skim southeastern Australia, southwestern Africa and southeastern South America; and sparingly touch the southwestern Pacific Ocean.

The instant of first external contact of the penumbra, the lunar shadow's outer and lighter portion, with Earth's surface initiates a solar eclipse's partial portion. According to the NASA Eclipse Web Site's eclipse predictions by NASA astrophysicist, now retired, Fred Espenak, the Saturday, Dec. 4, solar event's partial eclipse begins at 5:29:11.3 Universal Time (12:29 a.m. Eastern Standard Time; 2:29 a.m. Chile Summer Time; 4:29 a.m. Australian Eastern Daylight Time; 7:29 a.m. Central Africa Time and South Africa Standard Time).

The instant of first external contact of the umbra, the lunar shadow's innermost and darkest portion, with Earth's surface nudges the solar eclipse's total portion. The Saturday, Dec. 4, solar event's total eclipse begins at 7:00:01.0 UT (2:00 a.m. EST; 4:00 a.m. CLST; 6:00 a.m. AEDT; 9:00 a.m. CAT and SAST).

The instant of first internal contact of the umbra with Earth's surface occasion's the total eclipse's second significant umbral contact. This first internal umbral contact takes place at 7:05:48.9 UT (2:05 a.m. EST; 4:05 a.m. CLST; 6:05 a.m. AEDT; 9:05 a.m. CAT and SAST).

Greatest eclipse concerns the instant of closest passage of the lunar shadow cone's axis to Earth's center. The Saturday, Dec. 4, solar event's greatest eclipse takes place at 7:33:22.5 UT (2:33 a.m. EST; 4:33 a.m. CLST; 6:33 a.m. AEDT; 9:33 a.m. CAT and SAST).

The geographic coordinates at greatest eclipse are 76 degrees 46.7 minutes south latitude, 46 degrees 11.9 degrees west longitude. The coordinates place the Saturday, Dec. 4, greatest eclipse in the Weddell Sea, north of Berkner Island, also known as Berkner Ice Rise or Hubley Island.

At greatest eclipse, the moon's geocentric coordinates are right ascension of 16 hours 42 minutes 34.9 seconds and declination of minus 23 degrees 13 arcminutes 22.1 arcseconds. The sun's greatest eclipse geocentric coordinates are right ascension of 16 hours 43 minutes 32.3 seconds and declination of minus 22 degrees 16 arcminutes 29.3 arcseconds.

This greatest eclipse has a duration of 1 minute 54.4 seconds. At greatest eclipse, the path width measures 418.6 kilometers.

At greatest eclipse, the moon is in the constellation of Ophiuchus the Serpent Bearer, according to Fred Espenak's EclipseWise web site. Greatest eclipse precedes the lunar reach of perigee (Ancient Greek: περί, perí, “near” + γῆ, gê, “Earth”) by 0.1 days. According to Espenak's AstroPixels web site, perigee takes place Saturday, Dec. 4, 10:01 Greenwich Mean Time. The center-to-center distance of 356,794 kilometers between Earth and the moon qualifies as the year's minimum value, or closest distance, for perigee.

The instant of last internal contact of the umbra with Earth's surface marks the total eclipse's third significant umbral contact. This last internal umbral contact occurs at 8:00:40.9 UT (3:00 a.m. EST; 5:00 a.m. CLST; 7:00 a.m. AEDT; 10:00 a.m. CAT and SAST).

The instant of last external contact of the umbra with Earth's surface, which numbers as the total eclpse's fourth significant umbral contact, closes a solar eclipse's total portion. The Saturday, Dec. 4, solar event's total eclipse finishes at 08:06:29.2 UT (3:06 a.m. EST; 5:06 a.m. CLST; 7:06 a.m. AEDT; 10:06 a.m. CAT and SAST).

The instant of last external contact of the penumbra with Earth's surface terminates the partial solar eclipse. The Saturday, Dec. 4, solar event's partial eclipse ends at 9:37:23.9 UT (4:37 a.m. EST; 6:37 a.m. CLST; 8:37 a.m. AEDT; 11:37 a.m. CAT and SAST).

The end of the Saturday, Dec. 4, 2021, total solar eclipse marks the end of the year's eclipses. December's solar eclipse numbers as the fourth of the year's four eclipses and as the second of the year's two solar eclipses. The year's first solar eclipse took place Thursday, June 10, as an annular solar eclipse. The year's two lunar eclipses occurred Wednesday, May 26, and Friday, Nov. 19, as total and partial lunar eclipses, respectively.

The takeaways for the Saturday, Dec. 4, total solar eclipse are that it closes the 2021 eclipse quartet of two lunar and two solar eclipses; that the event's path of totality exclusively favors West Antarctica and the Antarctic Ocean; and that the event's path of partiality skims southernmost Africa, Australia and South America.

animation of total solar eclipse Saturday, Dec. 4, 2021: A.T. Sinclair/NASA, Public Domain, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Saturday, Dec. 4, 2021, total solar eclipse details; credit: "Permission is freely granted to reproduce this data when accompanied by an acknowledgment: Eclipse Predictions by Fred Espenak, NASA's GSFC," via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/SEplot/SEplot2001/SE2021Dec04T.GIF

animation of total solar eclipse Saturday, Dec. 4, 2021: A.T. Sinclair/NASA, Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:SE2021Dec04T.gif

For further information:

Beatty, J. Kelly. "Solar and Lunar Eclipses in 2021." Sky & Telescope > Observing > Celestial News & Events. Jan. 26, 2021.
Available @ https://skyandtelescope.org/observing/solar-and-lunar-eclipses-in-2021/

Celestial Chart. "Moon Phases." Celestial Chart > Ephemeris.
Available @ http://celestialchart.com/moon-phases/

Espenak, Fred. "Glossary of Solar Eclipse Terms." NASA Eclipse Web Site > Solar Eclipses.
Available @ https://eclipse.gsfc.nasa.gov/SEhelp/SEglossary.html

Espenak, Fred. "Key to Solar Eclipse Global Maps." NASA Eclipse Web Site > Solar Eclipses.
Available @ https://eclipse.gsfc.nasa.gov/SEplot/SEplotkey.html

Espenak, Fred. “Moon at Perigee and Apogee: 2001 to 2020 Greenwich Mean Time (GMT).” AstroPixels > Planetary Ephemeris Data > Moon > Perigee and Apogee: 2001-2100.
Available @ http://astropixels.com/ephemeris/moon/moonperap2001.html

Espenak, Fred. “Total Solar Eclipse of 2021 Dec 4.” EclipseWise > Solar Eclipses > Recent and Upcoming Solar Eclipses > Eclipses During 2021.
Available @ http://www.eclipsewise.com/solar/SEprime/2001-2100/SE2021Dec04Tprime.html

Espenak, Fred. “Total Solar Eclipse of 2021 Dec 4.” NASA Eclipse Web Site > Solar Eclipses > Solar Eclipses: Past and Future > Decade Solar Eclipse Tables > Solar Eclipses: 2021-2030.
Available @ https://eclipse.gsfc.nasa.gov/SEplot/SEplot2001/SE2021Dec04T.GIF

Marriner, Derdriu. "Friday, Nov. 19, Partial Lunar Eclipse Belongs to Saros Cycle 126." Earth and Space News. Wednesday, Nov. 10, 2021.
Available @ https://earth-and-space-news.blogspot.com/2021/11/friday-nov-19-partial-lunar-eclipse.html

Marriner, Derdriu. "Friday, Nov. 19, Partial Lunar Eclipse Is Second 2021 Lunar Eclipse." Earth and Space News. Wednesday, Nov. 3, 2021.
Available @ https://earth-and-space-news.blogspot.com/2021/11/friday-nov-19-partial-lunar-eclipse-is.html

Marriner, Derdriu. "May 26, 2021, Total Lunar Eclipse Belongs to Saros Cycle 121." Earth and Space News. Wednesday, May 26, 2021.
Available @ https://earth-and-space-news.blogspot.com/2021/05/may-26-2021-total-lunar-eclipse-belongs.html

Marriner, Derdriu. "May 26 Total Lunar Eclipse Is First of Two 2021 Lunar Eclipses." Earth and Space News. Wednesday, May 19, 2021.
Available @ https://earth-and-space-news.blogspot.com/2021/05/may-26-total-lunar-eclipse-is-first-of.html

Marriner, Derdriu. "Thursday, June 10, Annular Solar Eclipse Belongs to Saros Series 147." Earth and Space News. Wednesday, June 9, 2021.
Available @ https://earth-and-space-news.blogspot.com/2021/06/thursday-june-10-annular-solar-eclipse_01795210254.html

Marriner, Derdriu. "Thursday, June 10, Annular Solar Eclipse Is First 2021 Solar Eclipse." Earth and Space News. Wednesday, June 2, 2021.
Available @ https://earth-and-space-news.blogspot.com/2021/06/thursday-june-10-annular-solar-eclipse.html

Time and Date. "December 4, 2021 Total Solar Eclipse." Time and Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/solar/2021-december-4

Time and Date. "December 4, 2021 — Total Solar Eclipse — Cape Town, South Africa." Time and Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/in/south-africa/cape-town?iso=20211204

Time and Date. "December 4, 2021 — Total Solar Eclipse — Mafeteng, Lesotho." Time and Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/in/lesotho/mafeteng?iso=20211204

Time and Date. "December 4, 2021 — Total Solar Eclipse — Marion Island (Prince Edward Islands), South Africa." Time and Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/in/south-africa/marion-island-prince-edward-islands?iso=20211204

Time and Date. "December 4, 2021 — Total Solar Eclipse — Melbourne, Vic, Australia." Time and Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/in/australia/melbourne?iso=20211204

Time and Date. "December 4, 2021 — Total Solar Eclipse — Puerto Williams, Chile." Time and Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/in/chile/puerto-williams?iso=20211204

Time and Date. "December 4, 2021 — Total Solar Eclipse — Stanley, Falkland Islands." Time and Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/in/falkland/stanley?iso=20211204

Time and Date. "December 4, 2021 — Total Solar Eclipse — Walvis Bay, Namibia." Time and Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/in/namibia/walvis-bay?iso=20211204

Time and Date. "Time Zone Converter – Time Difference Calculator (Classic)." Time and Date > Time Zones.
Available @ https://www.timeanddate.com/worldclock/converter-classic.html

Thursday, June 10, Annular Solar Eclipse Is First 2021 Solar Eclipse

Summary: The Thursday, June 10, annular solar eclipse is the first 2021 solar eclipse and the second eclipse in a lineup of two lunar and two solar eclipses.

June 10, 2021, annular solar eclipse details: "Permission is freely granted to reproduce this data when accompanied by an acknowledgment: Eclipse Predictions by Fred Espenak, NASA's GSFC," via NASA Eclipse Web Site

The Thursday, June 10, annular solar eclipse is the first 2021 solar eclipse, which sandwiches between the year's first and second lunar eclipses as the second eclipse in the 2021 quartet of two lunar and two solar eclipses.

The eclipse's path of annularity favors the northernmost reaches of Earth's Northern Hemisphere. Northernmost Canada, northernmost Greenland, the North Pole and the northernmost Russian Far East enjoy visibility of the sun's fiery annulus (Latin: annulus, "little ring"; anus, "ring" + -ulus, diminutive noun suffix) around the moon. For Canada, the annular eclipe traverses Central Canada's northernmost Northern Ontario region in Ontario province and Nord-du-Québec (Northern Quebec) administrative region in western Quebec province as well as Northern Canada's Baffin Island and Ellesmere Island in Nunavut. For Greenland, the annular eclipse occurs over the far northern reaches of Avannaata municipality (Avannaata Kommunia) and of Northeast Greenland National Park (Greenlandic: Kalaallit Nunaanni nuna eqqissisimatitaq). For Russia, the annular eclipse prefers the Far Eastern Federal District's Magadan Oblast and Sakha Republic.

The Thursday, June 10, eclipse's path of annularity arches across the Arctic Ocean at the top of the world. The path takes in the Arctic Ocean's marginal East Siberian Sea, off the Republic of Sakha, and Lincoln Sea, between Canada's Ellesmere Island and northernmost Greenland. Hudson Bay and the Atlantic Ocean's Baffin Bay also fall within the path of annularity.

Outside the annular eclipse's narrow corridor of visibility, the Thursday, June 10, event offers visibility of a partial eclipse to northern North America, much of Europe and much of North, Central and East Asia. The North Atlantic Ocean is eligible for visibility of the partial eclipse. Morocco is the only African country within the path of partiality.

The June 2021 solar eclipse commences with first contact of the penumbra, the lunar shadow's outer and lighter part, with Earth's surface. The year's first solar eclipse begins Thursday, June 10, at 8:12:15.5 Universal Time (4:12 a.m. Eastern Daylight Time), according to the NASA Eclipse Web Site's eclipse predictions by NASA astrophysicist, now retired, Fred Espenak.

The event's annular eclipse begins at the instant of first external contact of the umbra, the lunar shadow's innermost and darkest part, with Earth's surface. This external umbral contact occurs at 9:49:43.4 UT (5:49 a.m. EDT).

Annularity, an annular eclipse's maximum phase, silhouettes the entirety of the smaller lunar disk against the larger solar ring. Annularity occurs in the period between second and third contacts between the umbra and Earth's surface.

The second umbral contact entails the first internal contact with the umbra. This first internal umbral contact takes place at 10:00:36.9 UT (6:00 a.m. EDT).

Greatest eclipse designates the instant of closest passage of the axis of the lunar shadow cone to Earth's center. Greatest eclipse for the Thursday, June 10, solar event takes place at 10:41:51 UT (6:41 a.m. EDT). Geographic coordinates of 80 degrees 48.9 minutes north latitude, 66 degrees 48.3 minutes west longitude place the greatest eclipse's local circumstances in the Kennedy Channel, an Arctic sea passage between Canada's most northerly island, Ellesmere, and northern Greenland.

At greatest eclipse, the path of annularity's width measures 527.1 kilometers. Greatest eclipse endures for 3 minutes 51.2 seconds.

The moon's geocentric coordinates at greatest eclipse are right ascension of 5 hours 14 minutes 53.5 seconds and declination of plus 23 degrees 51 arcminutes 21.8 arcseconds. The sun's geocentric coordinates at greatest eclipse are right ascension of 5 hours 15 minutes 31.4 seconds and declination of plus 23 degrees 2 arcminutes 37.1 arcseconds.

The annular eclipse's third contact concerns the last internal umbral contact. This closing of the annular eclipse's maximum phase happens at 11:22:53.4 UT (7:22 a.m. EDT).

The fourth umbral tangency, the instant of the last external contact of the lunar umbra with Earth's surface, marks the end of the annular eclipse. The eclipse's annular portion ceases at 11:33:44.7 UT (7:33 a.m. EDT).

The instant of last external contact of the lunar penumbra with Earth's surface closes the event's partial eclipse. The Thursday, June 10, event's partiality ends at 13:11:15.6 UT (9:11 a.m. EDT).

Solar eclipses require the moon's new phase. Syzygy (pronounce: si·zuh·jee), an alignment in which Earth and the sun sandwich the moon, renders the moon invisible from Earth's perspective.

During an annular eclipse, the moon and the sun exhibit essentially the same placement in the same zodiacal constellation. The Thursday, June 10, 2021, annular eclipse finds the moon and the sun with declinations (celestial equivalent of latitude) of 23 north and right ascensions (celestial equivalent of longitude) of 5 east in Taurus the Bull constellation.

The Thursday, June 10, 2021, annular solar eclipse follows the year's first eclipse, the total lunar eclipse of Wednesday, May 26, and precedes 2021's third eclipse, the partial lunar eclipse of Friday, Nov. 19. A total solar eclipse on Saturday, Dec. 4, numbers as 2021's second and last solar eclipse and as the fourth and last of the year's lineup of four eclipses.

The takeaways for the Thursday, June 10, annular solar eclipse are that it is the first 2021 solar eclipse; that the path of annularity favors the northernmost Northern Hemisphere; that the annular eclipse includes the North Pole in its path of annularity; that the year's second solar eclipse, occurring as a total eclipse Dec. 4, closes the year's lineup of two lunar eclipses and two solar eclipses.

animation of annular solar eclipse Thursday, June 10, 2021: A.T. Sinclair/NASA, Public Domain, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

June 10, 2021, annular solar eclipse details; credit: "Permission is freely granted to reproduce this data when accompanied by an acknowledgment: Eclipse Predictions by Fred Espenak, NASA's GSFC," via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/SEplot/SEplot2001/SE2021Jun10A.GIF

animation of annular solar eclipse Thursday, June 10, 2021: A.T. Sinclair/NASA, Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:SE2021Jun10A.gif

For further information:

Barnett, Amanda. "Reference Systems." NASA Science Solar System Exploration > Basics of Space Flight.
Available @ https://solarsystem.nasa.gov/basics/chapter2-2/

Espenak, Fred. “Annular Solar Eclipse of 2021 Jun 10.” EclipseWise > Solar Eclipses > Recent and Upcoming Solar Eclipses > Eclipses During 2021.
Available @ http://www.eclipsewise.com/solar/SEprime/2001-2100/SE2021Jun10Aprime.html

Espenak, Fred. “Annular Solar Eclipse of 2021 Jun 10.” NASA Eclipse Web Site > Solar Eclipses > Solar Eclipses: Past and Future > Decade Solar Eclipse Tables > Solar Eclipses: 2021-2030.
Available @ https://eclipse.gsfc.nasa.gov/SEplot/SEplot2001/SE2021Jun10A.GIF

Espenak, Fred. "Glossary of Solar Eclipse Terms." NASA Eclipse Web Site > Solar Eclipses.
Available @ https://eclipse.gsfc.nasa.gov/SEhelp/SEglossary.html

Espenak, Fred. "Key to Solar Eclipse Global Maps." NASA Eclipse Web Site > Solar Eclipses.
Available @ https://eclipse.gsfc.nasa.gov/SEplot/SEplotkey.html

Espenak, Fred. “Moon at Perigee and Apogee: 2001 to 2020 Greenwich Mean Time (GMT).” AstroPixels > Planetary Ephemeris Data > Moon > Perigee and Apogee: 2001-2100.
Available @ http://astropixels.com/ephemeris/moon/moonperap2001.html

King, Bob. "Right Ascension & Declination: Celestial Coordinates for Beginners." Sky & Telescope > Observing > Stargazing Basics.
Available @ https://skyandtelescope.org/astronomy-resources/right-ascension-declination-celestial-coordinates/

Marriner, Derdriu. "May 26, 2021, Total Lunar Eclipse Belongs to Saros Cycle 121." Earth and Space News. Wednesday, May 26, 2021.
Available @ https://earth-and-space-news.blogspot.com/2021/05/may-26-2021-total-lunar-eclipse-belongs.html

Marriner, Derdriu. "May 26 Total Lunar Eclipse Is First of Two 2021 Lunar Eclipses." Earth and Space News. Wednesday, May 19, 2021.
Available @ https://earth-and-space-news.blogspot.com/2021/05/may-26-total-lunar-eclipse-is-first-of.html

Marriner, Derdriu. "Sunday, June 21, Annular Solar Eclipse Is First 2020 Solar Eclipse." Earth and Space News. Wednesday, June 10, 2020.
Available @ https://earth-and-space-news.blogspot.com/2020/06/sunday-june-21-annular-solar-eclipse-is.html