April 20 Rare Hybrid Solar Eclipse Is First of Two 2023 Solar Eclipses

Summary: An April 20 rare hybrid solar eclipse is the first of two 2023 solar eclipses, with eastern hemisphere visibility in April and western in October.

The Thursday, April 20, 2023, hybrid solar eclipse's path of totality begins as an annular eclipse in the southern Indian Ocean, northeast of the Kerguelen Islands (French: officially, Archipel Kerguelen; commonly: Îles Kerguelen), a sub-Antarctic group of islands, part of the French Southern and Antarctic Lands (French: Terres australes et antarctiques françaises, TAAF) and France's only remaining overseas territory (French: Territoire d'outre-mer or TOM); Friday, Oct. 28, 2016, natural color image obtained via multi-national, NASA scientific research satellite Terra's MODIS (Moderate Resolution Imaging Spectroradiometer) instrument; NASA Earth Observatory image by Jesse Allen, using data from the Land Atmosphere Near real-time Capability for EOS (LANCE): Freely available for re-publication or re-use, via NASA Earth Observatory

An April 20 rare hybrid solar eclipse is the first of two 2023 solar eclipses, with April's eclipse favoring the eastern hemisphere and the October event occurring over the western hemisphere.

The Thursday, April 20, 2023, solar eclipse occurs as hybrid solar eclipse, with visibility as a partial solar eclipse outside of the narrow path of totality traced by the event's annular-total component. The path of totality has a width of 25 miles on Earth's surface, according to Forbes senior contributor Jamie Carter in "April’s Unique ‘Ningaloo Eclipse’ Explained: Your Ultimate Guide To 2023’s Only Total Solar Eclipse," published March 29, 2023. The hybrid solar eclipse begins in the southern Indian Ocean at sunrise and ends in the north central Pacific Ocean, near the equator and the International Date Line, at sunset, according to geographer and solar eclipse mapper Michael Zeiler in "Annular-Total Solar Eclipse of April 20, 2023," posted on GreatAmericanEclipse.com, the solar eclipse-themed website he co-publishes with Polly White.

Earth's curvature occasions a hybrid as the fourth type in the solar eclipse classification quartet that includes annular (solar ring around the lunar disk), partial (incomplete solar coverage) and total (complete solar obscuration). "Because Earth's surface is curved, sometimes an eclipse can shift between annular and total as the Moon’s shadow moves across the globe. This is called a hybrid solar eclipse," explains the NASA Solar System Exploration website.

Earth-based eclipse watchers within the path of totality view the hybrid as annular, broken annular or total, but not as a mixture. A hybrid solar eclipse describes an eclipse path, not a "visual event," according to retired NASA astrophysicist Fred Espenak's explanation in Carter's March 29, 2023, Forbes post. Broken annularity references the interruption of annularity's ring of fire by lunar topography.

The April 2023 hybrid solar eclipse avails totality to northwestern Australia, Timor Leste and eastern Indonesia. The hybrid's line of totality brushes over Western Australia state's North West Cape and journeys across eastern Timor Leste to Western New Guinea's West Papua (Indonesian: Papua Barat) and Papua provinces.

The path of totality makes first landfall at the Ningaloo Coast, a UNESCO World Heritage Site along the western edge of Western Australia's North West Cape, according to Michael Zeiler's Great American Eclipse page. The Schouten Islands (Indonesian: Kepulauan Biak) receive the path of totality's last landfall. Also known as Biak Islands or Geelvink Islands, the Schouten Islands lie in Papua province's Cenderawasih Bay (Indonesian: Teluk Cenderawasih, "Bird of Paradise Bay"). The path of totality exits on Biak Island, according to "Eclipse Map -- April 20, 2023," credited to National Solar Observatory (NSO), AURA (Association of Universities for Research in Astronomy) and National Science Foundation, and published on the National Solar Observatory's website. Biak Island is the largest of the three main islands in the Schouten Islands (Biak) archipelago.

Earth visibility chart for hybrid solar eclipse of April 20, 2023, by Fred Espenak/NASA's GSFC (Goddard Space Flight Center); current upload Oct. 23, 2011, 12:09 (original upload Nov. 30, 2009, 01:30) by SockPuppetForTomruen at en.wikipedia: Public Domain, via Wikimedia Commons

The hybrid solar eclipse begins with the instant of first external contact of Earth's limb by the moon's umbra (Latin: "shadow"), the darkest, innermost portion of the lunar shadow, according to NASA Eclipse Web Site's "Key to Solar Eclipse Global Maps" by Fred Espenak. Designated as U1, the first external contact occurs Thursday, April 20, 2023, at 02:36:56.2 Universal Time, according to NASA Eclipse Web Site's "Hybrid Solar Eclipse of 2023 April 23" graphic by Fred Espenak. Time conversions place the first external contact at 7:36 a.m., French Southern and Antarctic (Kerguelen [Islands]) Time; 10:26 a.m., Australia Western Standard Time; 11:26 a.m. East Timor Time and Eastern Indonesian [Waktu Indonesia Timur] Time; 2:26 p.m., Gilbert Island Time; Wednesday, April 19, 10:36 p.m., Eastern Daylight Time.

First external contact occurs on the southern Indian Ocean, northeast of the Kerguelen Islands (French: officially, Archipel Kerguelen; commonly: Îles Kerguelen). The sub-Antarctic group of islands is part of the French Southern and Antarctic Lands (French: Terres australes et antarctiques françaises, TAAF), France's only remaining overseas territory (French: Territoire d'outre-mer or TOM).

The instant of first internal contact of the lunar umbra with Earth's limb is designated as U2. This first internal tangency occurs at 02:37:03.0 UT (7:37 a.m., TFT [also known as KIT]; 10:37 a.m., AWST; 11:37 a.m. TLT and WIT; 2:37 p.m., GILT; Wednesday, April 19, 10:37 p.m., EDT).

Greatest eclipse is achieved at 04:16:37.5 UT (9:16 a.m., TFT [also known as KIT]; 12:16 p.m., AWST; 1:16 p.m. TLT and WIT; 4:16 p.m., GILT; Thursday, April 19, 12:16 a.m., EDT). Greatest eclipse endured for 1 minute 16.1 seconds. Greatest eclipse indicates the instant of closest passage of the axis of the lunar shadow to Earth's center, as defined by Fred Espenak on NASA Eclipse Web Site's "Key to Solar Eclipse Global Maps." Greatest eclipse takes place off the southern coast of Timor Leste in the Timor Sea, an arm of the southeastern Indian Ocean. Greatest eclipse's terrestrial coordinates are established at 9 degrees 35.4 minutes South, 125 degrees 48.4 minutes East (9 degrees 35 minutes 24.0 seconds South latitude, 125 degrees 48 minutes 24.0 seconds East longitude).

The instant of last internal contact of the lunar umbra with Earth's limb is designated as U3. This last internal tangency takes place at 05:56:23.1 UT (10:56 a.m., TFT [also known as KIT]; 1:56 p.m., AWST; 2:56 p.m. TLT and WIT; 5:56 p.m., GILT; 1:56 a.m., EDT).

The hybrid solar eclipse ends with the instant of last external contact of the lunar umbra with Earth's limb. Designated as U4, this last external tangency happens at 05:56:35.2 UT (10:56 a.m., TFT [also known as KIT]; 1:56 p.m., AWST; 2:56 p.m. TLT and WIT; 5:56 p.m., GILT; Thursday, April 20, 1:56 a.m., EDT).

The path of totality makes last contact with Earth's surface in the north central Pacific Ocean, northeast of Makin Island and southeast of the Marshall Islands' Knox and Mili atolls. Makin Island is positioned as the northernmost of the equator-straddling Republic of Kiribati's Gilbert Islands. The Marshall Islands (Marshallese: Aolepān Aorōkin Ṃajeḷ) and the Republic of Kiribati (Gilbertese: [Ribaberiki] Kiribati) are located in Oceania's Micronesia subregion.

The eclipse's annularity is visible at the path of totality's start and finish points, according to "Hybrid Solar Eclipse in April 2023 -- The Rarest of All," published April 1, 2023, on Vito Technology's Star Walk website. Transition points from annularity to totality occur in the southern Indian Ocean northeast of the Kerguelen Islands and in the north central Pacific near the Marshall Islands.

The Thursday, April 20, 2023, hybrid solar eclipse's path of totality ends in annularity in the north Pacific Ocean southeast of uninhabited Knox Atoll, southernmost atoll in the Ratak Chain of the Republic of the Marshall Islands (Marshallese: Aolepān Aorōkin Ṃajeḷ); NASA Photo ID ISS002-E-6658 image of (center) Knox Atoll with shallow Klee Passage and Mili Atoll (upper center), obtained Sunday, May 20, 2001, 23:31:12 GMT, with Kodak DCS460 Electronic Still Camera, at spacecraft altitude of 211 nautical miles (391 kilometers): Gateway to Astronaut Photography of Earth, Public Domain, via Wikimedia Commons

The April 2023 solar eclipse's partiality stretches from easternmost Asia and the western and central North Pacific Ocean southward through maritime southeast Asia and Oceania and beyond Australia and New Zealand to East Antarctica. In addition to its expansive Pacific Ocean visibility, April's partial solar eclipse extends across the northeastern and southern Indian Ocean and avails partiality to the Southern Ocean, also known as the Antarctic Ocean.

The instant of first external contact of Earth's limb with the lunar penumbra initiates the Thursday, April 20, 2023 partial solar eclipse. Designated as P1, this first external tangency occurs at 01:34:15.8 UT. (9:34 a.m., Hong Kong Time and Casey [Casey Station, East Antarctica] Time; 11: 34 a.m., Australian Eastern Standard Time; 1:34 p.m. New Zealand Standard Time; Wednesday, April 19, at 9:34 p.m. Eastern Daylight Time).

P2 indicates the instant of first internal contact of Earth's limb with the lunar penumbra. This first internal tangency takes place at 03:53:12.4 UT (11:53 a.m. HKT and CAST; 1:53 p.m. AEST; 3:53 p.m. NZST; Wednesday, April 19, at 11:54 p.m. EDT).

The instant of last internal contact of the lunar penumbra with Earth's limb is designated as P3. This last internal tangency happens at 04:40:30.7 UT (12:40 p.m. HKT and CAST; 2:40 p.m. AEST; 4:40 p.m. NZST; Thursday, April 20, at 12:40 a.m. EDT).

The April 2023 partial solar eclipse ends at the instant of last external contact of the lunar penumbra with Earth's limb. Designated as P4, this last external tangency is achieved at 06:59:13.5 UT (2:59 p.m. HKT and CAST; 4:59 p.m. AEST; 6:59 p.m. NZST; 2:59 a.m. EDT).

The April 2023 solar eclipse's partiality lasts almost 325 minutes (5 hours 24 minutes 57.7 seconds). The solar event's annularity-totality consumed almost 199 minutes (3 hours 19 minutes 39.0 seconds).

The Thursday, April 20, hybrid solar eclipse opened the 2023 eclipse lineup as the first of two solar eclipses and as the first of the year's four eclipses. The year's second eclipse occurs Friday, May 5, as a penumbral lunar eclipse. The year's second solar eclipse takes place Saturday, Oct. 14, as an annular eclipse. The year's second lunar eclipse, which happens Saturday, Oct. 28, as a partial eclipse, closes the 2023 eclipse quartet.

animation of April 20, 2023, hybrid solar eclipse; animation by British astronomer A. (Andrew) T. Sinclair for NASA Goddard Space Flight Center (GSFC): 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:

The Thursday, April 20, 2023, hybrid solar eclipse's path of totality begins as an annular eclipse in the southern Indian Ocean, northeast of the Kerguelen Islands (French: officially, Archipel Kerguelen; commonly: Îles Kerguelen), a sub-Antarctic group of islands, part of the French Southern and Antarctic Lands (French: Terres australes et antarctiques françaises, TAAF) and France's only remaining overseas territory (French: Territoire d'outre-mer or TOM); Friday, Oct. 28, 2016, natural color image obtained via multi-national, NASA scientific research satellite Terra's MODIS (Moderate Resolution Imaging Spectroradiometer) instrument; NASA Earth Observatory image by Jesse Allen, using data from the Land Atmosphere Near real-time Capability for EOS (LANCE): Freely available for re-publication or re-use, via NASA Earth Observatory @ https://earthobservatory.nasa.gov/images/89328/kerguelen-islands

Earth visibility chart for hybrid solar eclipse of April 20, 2023, by Fred Espenak/NASA's GSFC (Goddard Space Flight Center); current upload Oct. 23, 2011, 12:09 (original upload Nov. 30, 2009, 01:30) by SockPuppetForTomruen at en.wikipedia: Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:SE2023Apr20H.png; Fred Espenak/NASA Goddard Space Flight Center (GSFC), via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/SEplot/SEplot2001/SE2023Apr20H.GIF

The Thursday, April 20, 2023, hybrid solar eclipse's path of totality ends in annularity in the north Pacific Ocean southeast of uninhabited Knox Atoll, southernmost atoll in the Ratak Chain of the Republic of the Marshall Islands (Marshallese: Aolepān Aorōkin Ṃajeḷ); NASA Photo ID ISS002-E-6658 image of (center) Knox Atoll with shallow Klee Passage and Mili Atoll (upper center), obtained Sunday, May 20, 2001, 23:31:12 GMT, with Kodak DCS460 Electronic Still Camera, at spacecraft altitude of 211 nautical miles (391 kilometers): Gateway to Astronaut Photography of Earth, Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:KnoxAtoll.jpg; Gateway to Astronaut Photography of Earth @ https://eol.jsc.nasa.gov/SearchPhotos/photo.pl?mission=ISS002&roll=E&frame=6658

animation of April 20, 2023, hybrid solar eclipse; animation by British astronomer A. (Andrew) T. Sinclair for NASA Goddard Space Flight Center (GSFC): Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:SE2023Apr20H.gif

For further information:

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Available @ https://www.forbes.com/sites/jamiecartereurope/2023/03/29/aprils-unique-ningaloo-eclipse-explained-your-ultimate-guide-to-2023s-only-total-solar-eclipse/?sh=32e66d424221

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Davis, Phil; and Steve Carney. "Hybrid Solar Eclipse: Because Earth's surface is curved, sometimes an eclipse can shift between annular and total as the Moon’s shadow moves across the globe. This is called a hybrid solar eclipse." NASA Solar System Exploration > Solar System > Eclipses > About > Types. Page updated Dec. 21, 2022.
Available via NASA Solar System @ https://solarsystem.nasa.gov/eclipses/about-eclipses/types/

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