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; credit: Eclipse map/figure/table/predictions courtesy of Fred Espenak, NASA/Goddard Space Flight Center, from eclipse.gsfc.nasa.gov: No copyright, 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: Eclipse map/figure/table/predictions courtesy of Fred Espenak, NASA/Goddard Space Flight Center, from eclipse.gsfc.nasa.gov: No copyright, 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