May 26, 2021, Total Lunar Eclipse Belongs to Saros Cycle 121

Summary: The Wednesday, May 26, 2021, total lunar eclipse belongs to Saros cycle 121, a series of 82 similar lunar eclipses.

A penumbral eclipse on Oct. 6, 1047, opened Saros cycle 121's lineup of 82 similar eclipses; credit: "Eclipse map/figure/table/predictions courtesy of Fred Espenak, NASA/Goddard Space Flight Center, from eclipse.gsfc.nasa.gov.," via NASA Eclipse Web Site

The Wednesday, May 26, 2021, total lunar eclipse belongs to Saros cycle 121, which comprises 82 lunar eclipses displaying similar geometries.

The Saros cycle associates eclipses according to such similar geometries as occurrence at the same lunar node, or crossing point of the lunar orbit with Earth's orbit. Same Saros cycle eclipses share an approximately similar distance from Earth and correspondingly similar time of occurrence in the year. Families, known as series, are composed of similar eclipses.

Saros cycle 121 lunar eclipses occur at the moon's descending node, which represents the point of the moon's crossing to the south of Earth's orbit. Each Saros cycle 121 lunar eclipse reveals the moon's northward movement with respect to the node.

A Saros cycle approximates 6,585.3 days (18 years 11 days 8 hours). Saros cycle 121 specifically lasts for 1,460.44 years, according to the NASA Eclipse Web Site. Saros series 121's first eclipse appeared as a penumbral eclipse Oct. 6, 1047, with the lunar passage through the southern edge of Earth's penumbra (the lighter, outer region of Earth's shadow). The cycle's 82nd and final eclipse will take place March 18, 2508, near the penumbra's northern edge.

Saros cycle 121's 82 lunar eclipses observe an order of 20 penumbral, six partial, 29 total, seven partial and 20 penumbral. The cycle's first 20 lunar eclipses, occurring as penumbral eclipses, began Oct. 6, 1047, and ended April 29, 1390. Eclipses 21 through 26 of the series appeared as partials, between May 10, 1408, and July 3, 1498, respectively.

The Wednesday, May 26, 2021, lunar eclipse falls within Saros 121 cycle's set of 29 total lunar eclipses. The set opened July 13, 1516, with number 27 in the cycle's 82-member lineup. May's total lunar eclipse numbers as 55 in the cycle's membership of 82 eclipses and closes the cycle's totality set as the 29th and last total lunar eclipse in Saros 121.

The Saros cycle 121 predecessor of May's total lunar eclipse was the total lunar eclipse of Friday, May 16, 2003. The May 2003 total lunar eclipse numbered as 54 in Saros 121 cycle's 82-member lineup and as 28 in the cycle's 29-member set of total eclipses. The May 2003 event favored all of Central and South America, most of Antarctica, most of the Atlantic Ocean and some of the East Pacific Ocean with all-eclipse visibility.

The Saros cycle 121 successor of the Wednesday, May 26, 2021, total lunar eclipse will be a partial lunar eclipse on Monday, June 6, 2039. The June 2039 event numbers as 56 in Saros 121 cycle's 82-member lineup and as the first and opening eclipse of the cycle's second set of partial eclipses. This second set comprises seven partial lunar eclipses.

The eclipse predictions by now-retired NASA astrophysicist Fred Espenak and Belgian mathematical astronomer Jean Meeus on NASA’s Eclipse Web Site recognize the Wednesday, May 26, 2021, event as the total lunar eclipse with the shortest duration in Saros cycle 121. The May 2021 total eclipse lasted only 14 minutes 30 seconds. Contrastingly, the total lunar eclipse of Oct. 18, 1660, total lunar eclipse's duration of 1 hour 40 minutes 29 seconds qualifies it as the longest total lunar eclipse in Saros cycle 121.

Saros 121 cycle's 40 penumbral lunar eclipses open and close the cycle as two 20-member sets. The April 29, 1390, penumbral eclipse's duration of 4 hours 31 minutes 51 seconds qualifies as the longest enduring penumbral lunar eclipse in Saros 121 cycle's lineup of 40 penumbral eclipses. The April 1390 penumbral eclipse appeared as number 20 in the cycle's 82-member lineup and numbered as the 20th and last penumbral eclipse in the cycle's first set of 20 penumbral eclipses. Credit as the Saros cycle 121's shortest penumbral lunar eclipse will go to the March 18, 2508, penumbral eclipse. It lasts only 1 hour 4 minutes 50 seconds. The March 2508 event closes Saros cycle 121 as the 82nd and last member in the series and as the 20th and last of the cycle's second set of penumbral lunar eclipses.

Saros cycle 121 offers two sets of partial lunar eclipses. The first set comprises six eclipses. The second set contains seven eclipses. The longest partial lunar eclipse occurred July 3, 1498, with a duration of 3 hours 10 minutes 47 seconds. The July 1498 eclipse appeared as number 26 in Saros 121 cycle's 82-member lineup and as the sixth and last eclipse in the cycle's first set of partial eclipses. The shortest partial lunar eclipse will take place Aug. 11, 2147, with a duration of 1 hour 6 minutes 1 second. The August 2147 event occurs as number 62 in Saros 121 cycle's 82-member lineup and as the seventh and last eclipse in the cycle's second set of partial lunar eclipses.

The takeaways for the Wednesday, May 26, 2021, total lunar eclipse's belonging to Saros cycle 121 are that the event occurs as number 55 in the cycle's lineup of 82 members; that the May 2021 eclipse numbers as the 29th and last member of the cycle's set of total lunar eclipses; and that the May 2021 eclipse's duration of only 14 minutes 30 seconds qualifies as the cycle's shortest total lunar eclipse.

A penumbral eclipse on March 18, 2508, will close Saros cycle 121 as the cycle's 82nd and last member; credit: "Eclipse map/figure/table/predictions courtesy of Fred Espenak, NASA/Goddard Space Flight Center, from eclipse.gsfc.nasa.gov.," via NASA Eclipse Web Site

Acknowledgment

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

Image credits:

A penumbral eclipse on Oct. 6, 1047, opened Saros cycle 121's lineup of 82 similar eclipses; credit: "Eclipse map/figure/table/predictions courtesy of Fred Espenak, NASA/Goddard Space Flight Center, from eclipse.gsfc.nasa.gov.," via NASA Eclipse Web Site (https://eclipse.gsfc.nasa.gov/SEpubs/copyright.html) @ https://eclipse.gsfc.nasa.gov/5MCLEmap/1001-1100/LE1047-10-06N.gif

A penumbral eclipse on March 18, 2508, will close Saros cycle 121 as the cycle's 82nd and last member; credit: "Eclipse map/figure/table/predictions courtesy of Fred Espenak, NASA/Goddard Space Flight Center, from eclipse.gsfc.nasa.gov.," via NASA Eclipse Web Site (https://eclipse.gsfc.nasa.gov/SEpubs/copyright.html) @ https://eclipse.gsfc.nasa.gov/5MCLEmap/2501-2600/LE2508-03-18N.gif

For further information:

Espenak, Fred. "Partial 1498 Jul 03.” NASA Eclipse Web Site > Lunar Eclipses > Lunar Eclipse Catalogs > Catalog of Lunar Eclipse Saros Series > Summary of Saros Series 101 to 125 > 26 1498 Jul 03.
Available @ https://eclipse.gsfc.nasa.gov/5MCLEmap/1401-1500/LE1498-07-03P.gif

Espenak, Fred. "Partial 2039 Jun 06.” NASA Eclipse Web Site > Lunar Eclipses > Lunar Eclipse Catalogs > Catalog of Lunar Eclipse Saros Series > Summary of Saros Series 101 to 125 > 56 2039 Jun 06.
Available @ https://eclipse.gsfc.nasa.gov/5MCLEmap/2001-2100/LE2039-06-06P.gif

Espenak, Fred. "Partial 2147 Aug 11.” NASA Eclipse Web Site > Lunar Eclipses > Lunar Eclipse Catalogs > Catalog of Lunar Eclipse Saros Series > Summary of Saros Series 101 to 125 > 62 2147 Aug 11.
Available @ https://eclipse.gsfc.nasa.gov/5MCLEmap/2101-2200/LE2147-08-11P.gif

Espenak, Fred. "Penumbral 1047 Oct 06.” NASA Eclipse Web Site > Lunar Eclipses > Lunar Eclipse Catalogs > Catalog of Lunar Eclipse Saros Series > Summary of Saros Series 101 to 125 > 01 1047 Oct 06.
Available @ https://eclipse.gsfc.nasa.gov/5MCLEmap/1001-1100/LE1047-10-06N.gif

Espenak, Fred. "Penumbral 2508 Mar 18.” NASA Eclipse Web Site > Lunar Eclipses > Lunar Eclipse Catalogs > Catalog of Lunar Eclipse Saros Series > Summary of Saros Series 101 to 125 > 82 2508 Mar 18.
Available @ https://eclipse.gsfc.nasa.gov/5MCLEmap/2501-2600/LE2508-03-18N.gif

Espenak, Fred. "Penumbral (T) 1390 Apr 29.” NASA Eclipse Web Site > Lunar Eclipses > Lunar Eclipse Catalogs > Catalog of Lunar Eclipse Saros Series > Summary of Saros Series 101 to 125 > 20 1390 Apr 29.
Available @ https://eclipse.gsfc.nasa.gov/5MCLEmap/1301-1400/LE1390-04-29N.gif

Espenak, Fred. “Saros 121.” EclipseWise Web Site > Lunar Eclipses > Lunar Eclipse Links > Saros Catalog of Lunar Eclipses > Summary of Saros Series 121 to 150 > Catalog of Lunar Eclipses of Saros 121.
Available @ http://www.eclipsewise.com/lunar/LEsaros/LEsaros121.html

Espenak, Fred. “Saros Series 121.” NASA Eclipse Web Site > Lunar Eclipses > Lunar Eclipse Catalogs > Catalog of Lunar Eclipse Saros Series > Summary of Saros Series 101 to 125.
Available @ http://www.eclipsewise.com/lunar/LEsaros/LEsaros121.html

Espenak, Fred. "Total 1516 Jul 13.” NASA Eclipse Web Site > Lunar Eclipses > Lunar Eclipse Catalogs > Catalog of Lunar Eclipse Saros Series > Summary of Saros Series 101 to 125 > 27 1516 Jul 13.
Available @ https://eclipse.gsfc.nasa.gov/5MCLEmap/1501-1600/LE1516-07-13T.gif

Espenak, Fred. "Total 1660 Oct 18.” NASA Eclipse Web Site > Lunar Eclipses > Lunar Eclipse Catalogs > Catalog of Lunar Eclipse Saros Series > Summary of Saros Series 101 to 125 > 35 1660 Oct 18.
Available @ https://eclipse.gsfc.nasa.gov/5MCLEmap/1601-1700/LE1660-10-18T.gif

Espenak, Fred. "Total 2003 May 16.” NASA Eclipse Web Site > Lunar Eclipses > Lunar Eclipse Catalogs > Catalog of Lunar Eclipse Saros Series > Summary of Saros Series 101 to 125 > 54 2003 May 16.
Available @ https://eclipse.gsfc.nasa.gov/5MCLEmap/2001-2100/LE2003-05-16T.gif

Espenak, Fred. “Total Lunar Eclipse of 2021 May 26.” EclipseWise > Lunar Eclipses > Recent and Upcoming Lunar Eclipses > Lunar Eclipse Preview: 2018 Through 2030.
Available @ http://www.eclipsewise.com/lunar/LEprime/2001-2100/LE2021May26Tprime.html

Espenak, Fred. “Total Lunar Eclipse of 2021 May 26.” NASA Eclipse Web Site > Lunar Eclipses: Past and Future > Decade long tables of past and future lunar eclipses > 2021-2030.
Available @ https://eclipse.gsfc.nasa.gov/LEplot/LEplot2001/LE2021May26T.pdf

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