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Solar eclipse of May 20, 2012

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Solar eclipse of May 20, 2012
Solar Eclipse May 20,2012.jpg
Composite image taken from Red Bluff, California
Type of eclipse
Maximum eclipse
Duration346 sec (5 m 46 s)
Coordinates49°06′N 176°18′E / 49.1°N 176.3°E / 49.1; 176.3
Max. width of band237 km (147 mi)
Times (UTC)
(P1) Partial begin20:56:07
(U1) Total begin22:06:17
Greatest eclipse23:53:54
(U4) Total end1:39:11
(P4) Partial end2:49:21
Saros128 (58 of 73)
Catalog # (SE5000)9535

The solar eclipse of May 20, 2012 (May 21, 2012 local time in the Eastern Hemisphere) was an annular solar eclipse that was visible in a band spanning through Eastern Asia, the Pacific Ocean, and North America. As a partial solar eclipse, it was visible from northern Greenland to Hawaii, and from eastern Indonesia at sunrise to northwestern Mexico at sunset. The moon's apparent diameter was smaller because the eclipse was occurring only 32 1/2 hours after apogee.

A solar eclipse is an astronomical phenomenon that occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. An annular solar eclipse occurs when the Moon's apparent diameter is smaller than the Sun's, blocking most of the Sun's light and causing the Sun to look like an annulus (ring). An annular eclipse appears as a partial eclipse over a region of the Earth thousands of kilometres wide.

The annular eclipse was the first visible from the contiguous United States since the solar eclipse of May 10, 1994 (Saros 128), and the first in Asia since the solar eclipse of January 15, 2010 (Saros 141).[1] The path of the eclipse's antumbra included heavily populated regions of China and Japan, and an estimated 100 million people in those areas were capable of viewing annularity. In the western United States, its path included 8 states, and an estimated 6 million people were capable of viewing annularity. It was the 58th eclipse of the 128th Saros cycle, which began with a partial eclipse on August 29, 984 AD and will conclude with a partial eclipse on November 1, 2282.

Visibility and viewing[edit]

Animation of the eclipse

The antumbra had a magnitude of .94, stretched 236 kilometres (147 mi) wide, and traveled eastbound at an average rate of 1.00 kilometre (0.62 mi) per second, remaining north of the equator throughout the event. The longest duration of annularity was 5 minutes and 43 seconds, occurring just south of the Aleutian Islands.[2] The eclipse began on a Monday and ended on the previous Sunday, as it crossed the International Date Line.[1]


The annular eclipse commenced over the Chinese province of Hainan at sunrise, at 6:06 a.m. China Standard Time. Travelling northeast, antumbra of the eclipse approached and passed over the cities of Guangzhou, Hong Kong, and Xiamen, reaching Taipei, Taiwan by 6:10 a.m NST. After crossing the East China Sea, it passed over much of eastern Japan, including Nagoya and Tokyo at 7:28 a.m and 7:32 a.m JST respectively, before entering the Pacific Ocean. The penumbra of the eclipse was visible throughout Eastern Asia and various islands in the Pacific Ocean until noon.[3][4]

The path of the antumbra over highly populated areas allowed at least an estimated 100 million people to view annularity.[5] Because the eclipse took place during the summer monsoon season in Southeast Asia, viewing conditions were not ideal in some areas, including Hong Kong.[6]

North America[edit]

After traveling approximately 4,000 miles (6,500 kilometers) across the Pacific Ocean, the antumbra entered North America between the coastlines of Oregon and California, reaching the coastal city of Eureka, California at 6:28 p.m PDT. After passing over Medford, Oregon and Redding, California, it had reached Reno, Nevada by 6:31 p.m PDT. The eclipse continued to travel southeast, passing 30 miles (48 km) north of Las Vegas, Nevada, over St. George, Utah, and reaching the Grand Canyon by approximately 6:35 p.m MST. After passing over Albuquerque, New Mexico and Lubbock, Texas, the eclipse terminated above central Texas at sunset, 8:39 p.m. CST.[3][2][7] An estimated 6.6 million people lived under the path of the antumbra.[8] The penumbra was visible throughout most of North America, including the islands of Hawaii.[2]

Eclipse Characteristics[edit]

Eclipse Magnitude = 0.94390

Eclipse Obscuration = 0.89094

Gamma = 0.48279

Saros Series = 128th (58 of 73)

Conjunction Times[edit]

Greatest Eclipse = 20 May 2012 23:52:46.8 UTC (20 May 2012 23:53:53.6 TD)

Ecliptic Conjunction = 20 May 2012 23:47:01.3 UTC (20 May 2012 23:48:08.1 TD)

Equatorial Conjunction = 20 May 2012 23:59:09.5 UTC (21 May 2012 00:00:16.3 TD)

Geocentric Coordinates of Sun and Moon[edit]

Sun right ascension = 3 hours, 52 minutes, 43.0 seconds

Moon right ascension = 3 hours, 52 minutes, 30.7 seconds

Earth's shadow right ascension = 15 hours, 52 minutes, 43.0 seconds

Sun declination = 20 degrees, 13 minutes, 15.1 seconds north of Celestial Equator

Moon declination = 20 degrees, 39 minutes, 6.3 seconds north of Celestial Equator

Earth's shadow declination = 20 degrees, 13 minutes, 15.1 seconds south of Celestial Equator

Sun diameter = 1896.2 arcseconds

Moon diameter = 1766.6 arcseconds

Geocentric Libration of the Moon[edit]

Latitude: 1.3 degrees south

Longitude: 0.6 degrees west

Direction: 346.3 (NNW)

Related eclipses[edit]

Eclipses of 2012[edit]

Solar eclipses 2011–2014[edit]

This eclipse is a member of the 2011–2014 solar eclipse semester series. An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.[9][Note 1]

Saros 128[edit]

This eclipse is a member of the Solar Saros cycle 128, which includes 73 eclipses occurring in intervals of 18 years and 11 days. The series started with partial solar eclipse on August 29, 984 AD. From May 16, 1417 through June 18, 1471 the series produced total solar eclipses, followed by hybrid solar eclipses from June 28, 1489 through July 31, 1543, and annular solar eclipses from August 11, 1561 through July 25, 2120. The series ends at member 73 as a partial eclipse on November 1, 2282. All eclipses in this series occurs at the Moon’s descending node.

Tritos series[edit]

This eclipse is a part of a tritos cycle, repeating at alternating nodes every 135 synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee), but groupings of 3 tritos cycles (≈ 33 years minus 3 months) come close (≈ 434.044 anomalistic months), so eclipses are similar in these groupings.

Metonic series[edit]

The metonic series repeats eclipses every 19 years (6939.69 days), lasting about 5 cycles. Eclipses occur in nearly the same calendar date. In addition, the octon subseries repeats 1/5 of that or every 3.8 years (1387.94 days). All eclipses in this table occur at the Moon's descending node.[10]

Inex series[edit]

This eclipse is a part of the long period inex cycle, repeating at alternating nodes, every 358 synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee). However, groupings of 3 inex cycles (≈ 87 years minus 2 months) comes close (≈ 1,151.02 anomalistic months), so eclipses are similar in these groupings.


  1. ^ The partial solar eclipses of January 4, 2011 and July 1, 2011 occurred in the previous semester series.


  1. ^ a b Friedlander, Blaine (May 20, 2012). "Annular solar eclipse first in 18 years in continental United States on May 20". The Washington Post. Archived from the original on July 19, 2012. Retrieved May 20, 2012.
  2. ^ a b c "Annular Solar Eclipse of 2012 May 20". NASA Goddard Space Flight Center Eclipse Website. NASA. May 20, 2012. Retrieved May 20, 2012.
  3. ^ a b "Eclipse Map - May 20–21 Solar Eclipse". Retrieved 20 May 2012.
  4. ^ Matsutani, Minoru (May 20, 2012). "Tokyo to be treated to rare annular eclipse, Venus transit". The Japan Times. Retrieved 20 May 2012.
  5. ^ Beatty, Kelly (May 20, 2012). "May 20th's Annular Eclipse of the Sun". Sky and Telescope. Retrieved May 20, 2012.
  6. ^ "May the Sun Shine on Rare Eclipse". South China Morning Post. May 20, 2012. Retrieved 20 May 2012.
  7. ^ Potter, Ned (May 20, 2012). "Solar Eclipse Visible From California to Texas Sunday Afternoon". ABC News. Retrieved May 20, 2012.
  8. ^ Tariq, Malik (May 20, 2012). "Spectacular "Ring of Fire" Solar Eclipse Wows Millions". Retrieved May 20, 2012.
  9. ^ van Gent, R.H. "Solar- and Lunar-Eclipse Predictions from Antiquity to the Present". A Catalogue of Eclipse Cycles. Utrecht University. Retrieved 6 October 2018.
  10. ^ Freeth, Tony. "Note S1: Eclipses & Predictions". Retrieved 6 October 2018.