Dec. 3, 1918, Annular Eclipse Was Second of Two 1918 Solar Eclipses

Summary: The Dec. 3, 1918, annular eclipse was the second of two 1918 solar eclipses, of which the first was total, and was fourth of the year's five eclipses.

Tuesday, Dec. 3, 1918, annular solar eclipse details: Eclipse Predictions by Fred Espenak, NASA's GSFC, via NASA Eclipse Web Site

The Tuesday, Dec. 3, 1918, annular eclipse was the second of two 1918 solar eclipses, of which the first was the Saturday, June 8, total solar eclipse, and was the fourth of the year's quintet of three lunar and two solar eclipses.

The Tuesday, Dec. 3, 1918, annular solar eclipse's path of annularity favored the Southern Hemisphere. The path swept across the South Pacific Ocean's central eastern expanses to touch the capitals of all three South American countries through which it passed: Santiago, Chile; Buenos Aires, Argentina; Montevideo, Uruguay. After crossing the South Atlantic Ocean, the path of annularity scooted to northeastern South West Africa (Republic of Namibia since March 21, 1990) and southwestern Portuguese West Africa (Republic of Angola since Nov. 11, 1975) for liftoff.

The Tuesday, Dec. 3, 1918, solar event's partial eclipse stretched northward across the Equator and southward to Antarctica. Northern limits expanded the path of partiality's continental reach from South America into North America's Central America (Panama, Costa Rica, Nicaragua, Guatemala) and Southwest Mexico, according to TheSkyLive website's map. Southern limits expanded the path of partiality's oceanic reach from the South Atlantic and South Pacific oceans into the Southern Ocean and the southwestern Indian Ocean.

The Tuesday, Dec. 3, 1918, solar eclipse disfavored the continents of Asia, Australia and Europe. The Arctic Ocean also was excluded from eclipse visibility.

The Tuesday, Dec. 3, 1918, solar event began with a partial eclipse at 12:21:05.0 Universal Time (7:21 a.m. Eastern Standard Time), according to NASA Eclipse Web Site's eclipse predictions by Goddard Space Flight Center (GSFC) astrophysicist, now retired, Fred Espenak. The instant of first external contact of the lunar penumbra (lighter, outer shadow) with Earth's limb, designated as P1, initiates a partial solar eclipse.

The December 1918 solar event's annular eclipse began at 13:25:52.9 UT (8:25 a.m. EST). The instant of first external contact of the lunar umbra (darker, inner shadow) with Earth's limb, designated as U1, starts an annular solar eclipse.

Annularity defines as an annular solar eclipse's maximum phase, characterized by the silhouette of the entire lunar disk against the sun. Annularity timelines between the annular eclipse's second and third umbral contacts, explains Fred Espenak in NASA Eclipse Web Site's Glossary of Solar Eclipse Terms. The second and third umbral contacts pertain to internal umbral tangency.

The Tuesday, Dec. 3, 1918, annular solar eclipse registered greatest eclipse at 15:21:39.7 UT (10:21 a.m. EST). Greatest eclipse denotes the instant of closest passage of the lunar shadow's axis to Earth's center.

Greatest eclipse's geographic coordinates of 36 degrees 02.9 minutes south latitude at 53 degrees 41.4 minutes west longitude place the event in the western South Atlantic Ocean, southeast of the Uruguayan capital of Montevideo. The local circumstances at greatest eclipse revealed the event's duration at 7 minutes 05.7 seconds and the path of annularity's width at 236.4 kilometers.

At greatest eclipse, the moon's geocentric coordinates were right ascension of 16 hours 36 minutes 14.7 seconds and declination of minus 22 degrees 16 arcminutes 22.6 arcseconds. The sun's geocentric coordinates were right ascension of 16 hours 36 minutes 17.1 seconds and declination of minus 22 degrees 3 arcminutes 17.0 arcseconds.

The Tuesday, Dec. 3, 1918, annular solar eclipse's second umbral contact, designated as U2, took place at 13:31:19.3 UT (8:31 a.m. EST). An annular eclipse's second umbral contact numbers as the first internal contact of the lunar umbra with Earth's limb.

The Tuesday, Dec. 3, 1918, annular solar eclipse's third umbral contact, designated as U3, occurred at 17:12:00.7 UT (12:12 p.m. EST). An annular eclipse's third umbral contact sequences as the last internal contact of the lunar umbra with Earth's limb.

The Tuesday, Dec. 3, 1918, solar event's annular eclipse ended at 17:17:22.5 UT (12:17 p.m. EST). The instant of last external contact of the lunar umbra with Earth's limb, designated as U4, announces the annular phase's completion.

During annularity's internal umbral contacts, the Tuesday, Dec. 3, 1918, solar event's partial eclipse experienced interior penumbral contacts. The two significant internal penumbral contacts are not present in all solar eclipses, according to the NASA Eclipse Web Site. Their presence associates with the complete casting of the lunar penumbra within Earth's disk.

The instant of first internal contact of the lunar penumbra with Earth's limb, designated as P2, happened at 14:39:57.9 UT (9:39 a.m. EST). The instant of last internal contact of the lunar penumbra with Earth's limb, designated as P3, took place at 16:03:20.4 UT (11:03 a.m. EST).

The Tuesday, Dec. 3, 1918, solar event's partial eclipse terminated at 18:22:08.1 UT (1:22 p.m. EST). The instant of last external contact of the lunar penumbra with Earth's limb, designated as P4, signals the end of a partial solar eclipse.

Fred Espenak's EclipseWise website notes solar and lunar details of the Tuesday, Dec. 3, 1918, solar eclipse as placement of the sun in Ophiuchus the Serpent Bearer constellation and as occurrence of lunar apogee 4.3 days earlier. Apogee (Ancient Greek: ἀπόγειον, apógeion, “away from Earth” + ἀπό, apó, “away” + γῆ, gê, “Earth”), the farthest center-to-center distance between the moon and Earth, was reached Friday, Nov. 29, at 7:12 UTC (2:12 a.m. EST), at a distance of 405,647 kilometers, according to computer programmer John Walker's Fourmilab Switzerland website.

The Tuesday, Dec. 3, 1918, annular solar eclipse appeared as the second of the year's two solar eclipses. The year's first solar eclipse occurred as a total solar eclipse on Saturday, June 8, 1918, and opened the 2021 lineup of five eclipses. A partial lunar eclipse on Monday, June 24, numbered as the year's first lunar eclipse as second in the 2021 five-member lineup. The almost lunar eclipse of Sunday, Nov. 17, to Monday, Nov. 18, occurred as the year's second lunar eclipse and as third in the 2021 eclipse lineup.

The NASA Eclipse Web Site and Fred Espenak's EclipseWise web sites make no mention of November's almost lunar event. Time and Date website includes the event in the year's eclipse tally but notes that a lunar eclipse was not visible from Earth. The alignment of sun, Earth and moon was close but not enough for Earth-based visibility of contact between Earth's shadow and the moon. Time and Date notes that "some sources" consider the event as a penumbral lunar eclipse.

The penumbral lunar eclipse of Tuesday, Dec. 17, followed the Tuesday, Dec. 3, 1918, annular solar eclipse. The December lunar eclipse numbered as the third of the year's three lunar eclipses and closed the year's eclipse lineup as the fifth of the year's five eclipses.

The takeaways for the Dec. 3, 1918, annular solar eclipse are that it was the second of two 1918 solar eclipses; that the path of annularity favored the Southern Hemisphere, tracked across the capitals of three South American countries and lifted off in southwestern Angola (then Portuguese West Africa); that the path of totality added North America to the event's continental audience; and that the Tuesday, Dec. 3 solar eclipse was succeeded, two weeks later, by the year's closing eclipse, the Tuesday, Dec. 17, penumbral lunar eclipse.

Tuesday, Dec. 3, 1918, annular solar eclipse's Southern Hemisphere path of annularity and Northern Hemisphere-Southern Hemisphere path of partiality: Eclipse Predictions by Fred Espenak (NASA's GSFC), 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:

Tuesday, Dec. 3, 1918, annular solar eclipse details: Eclipse Predictions by Fred Espenak, NASA's GSFC, via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/SEplot/SEplot1901/SE1918Dec03A.GIF

Tuesday, Dec. 3, 1918, annular solar eclipse's Southern Hemisphere path of annularity and Northern Hemisphere-Southern Hemisphere path of partiality: Eclipse Predictions by Fred Espenak (NASA's GSFC), via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/5MCSEmap/1901-2000/1918-12-03.gif

For further information:

Espenak, Fred. "Annular 1918 Dec 03." NASA Eclipse Web Site > Solar Eclipses > Decade Tables of Solar Eclipses > Solar Eclipses: 1911-1920 > Solar Eclipse Catalogs > Saros Catalog of Solar Eclipses: Saros 0-180 > Summary of Saros Series 125 to 150 > Saros Series 131 > Catalog of Solar Eclipses of Saros 131.
Available @ https://eclipse.gsfc.nasa.gov/5MCSEmap/1901-2000/1918-12-03.gif

Espenak, Fred. "Annular Solar Eclipse of 1918 Dec 03." EclipseWise Website > Solar Eclipses > Solar Eclipse Links > Decade Pages of Solar Eclipses > Solar Eclipses: 1911-1920.
Available @ http://www.eclipsewise.com/solar/SEprime/1901-2000/SE1918Dec03Aprime.html

Espenak, Fred. "Annular Solar Eclipse of 1918 Dec 03." NASA Eclipse Web Site > Solar Eclipses > Decade Tables of Solar Eclipses > Solar Eclipses: 1911-1920.
Available @ https://eclipse.gsfc.nasa.gov/SEplot/SEplot1901/SE1918Dec03A.GIF

Espenak, Fred. "Glossary of Solar Eclipse Terms." NASA Eclipse Web Site.
Available @ https://eclipse.gsfc.nasa.gov/help/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. "Solar Eclipse Figures." NASA Eclipse Web Site.
Available @ https://eclipse.gsfc.nasa.gov/OH/OHres/SEfigurekeyP.html

Marriner, Derdriu. "Saturday, June 8, 1918, Total Solar Eclipse Belongs to Saros Cycle 126." Earth and Space News. Wednesday, June 23, 2021.
Available @ https://earth-and-space-news.blogspot.com/2021/06/saturday-june-8-1918-total-solar.html

Marriner, Derdriu. "Total Solar Eclipse June 8, 1918, Was First of Two 1918 Solar Eclipses." Earth and Space News. Wednesday, June 16, 2021.
Available @ https://earth-and-space-news.blogspot.com/2021/06/total-solar-eclipse-june-8-1918-was.html

TheSkyLive. "Solar Eclipse of December 3 1918." TheSkyLive > Solar Eclipses > Solar Eclipses Browse by decade: 1910-1919.
Available @ https://theskylive.com/solar-eclipse?id=1918-12-03

Time and Date. "November 17–18, 1918 Almost Lunar Eclipse." Time and Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/lunar/1918-november-18

Time and Date. "December 3, 1918 Annular Solar Eclipse." Time and Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/solar/1918-december-3

Time and Date. "December 3, 1918 — Annular Solar Eclipse — San Jose, Costa Rica." Time and Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/in/costa-rica/san-jose?iso=19181203

Walker, John. "Lunar Perigee and Apogee Calculator." Fourmilab Switzerland > Earth and Moon Viewer and Solar System Explorer.
Available @ https://www.fourmilab.ch/earthview/pacalc.html