Solar eclipse of May 20, 2012

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.

Solar eclipse of May 20, 2012
Composite image taken from Red Bluff, California
Map
Type of eclipse
NatureAnnular
Gamma0.4828
Magnitude0.9439
Maximum eclipse
Duration346 sec (5 m 46 s)
Coordinates49.1°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
References
Saros128 (58 of 73)
Catalog # (SE5000)9535

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
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]

Asia

The annular eclipse commenced over the Chinese province of Guangxi at sunrise, at 6:06 a.m. China Standard Time. Travelling northeast, the antumbra of the eclipse approached and passed over the cities of Macau, Hong Kong, Guangzhou, and Xiamen, reaching Taipei by 6:10 a.m NST. After crossing the East China Sea, it passed over much of eastern Japan, including Osaka 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

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 6:25 p.m PDT. After passing over Medford, Oregon and Redding, California, it had reached Reno, Nevada by 6:28 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 6:33 p.m MST. After passing over Albuquerque, New Mexico and Lubbock, Texas, the eclipse terminated above central Texas at sunset, 8:38 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]

Eclipses of 2012

Solar eclipses 2011–2014

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]

Solar eclipse series sets from 2011–2014
Descending node   Ascending node
Saros Map Gamma Saros Map Gamma
118

Partial from Tromsø, Norway		 2011 June 01

Partial (north)		 1.21300 123 2011 November 25

Partial (south)		 -1.05359
128

Middlegate, Nevada		 2012 May 20

Annular		 0.48279 133

Cairns, Australia		 2012 November 13

Total		 -0.37189
138

Churchills Head, Australia		 2013 May 10

Annular		 -0.26937 143

Partial from Libreville, Gabon		 2013 November 03

Hybrid		 0.32715
148

Partial from Adelaide, Australia		 2014 April 29

Annular (non-central)		 -0.99996 153

Partial from Minneapolis		 2014 October 23

Partial (north)		 1.09078

Saros 128

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.

Series members 52–68 occur between 1901 and 2200
52 53 54

March 17, 1904
March 28, 1922
April 7, 1940
55 56 57

April 19, 1958
April 29, 1976
May 10, 1994
58 59 60

May 20, 2012
June 1, 2030
June 11, 2048
61 62 63

June 22, 2066
July 3, 2084
July 15, 2102
64 65 66

July 25, 2120		 August 5, 2138 (Partial) August 16, 2156 (Partial)
67 68
August 27, 2174 (Partial) September 6, 2192 (Partial)

Tritos series

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

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]

Octon series with 21 events between May 21, 1993 and August 2, 2065
May 20–21 March 8–9 December 25–26 October 13–14 August 1–2
98 100 102 104 106
May 21, 1955 March 9, 1959 December 26, 1962 October 14, 1966 August 2, 1970
108 110 112 114 116
May 21, 1974 March 9, 1978 December 26, 1981 October 14, 1985 August 1, 1989
118 120 122 124 126

May 21, 1993
March 9, 1997
December 25, 2000
October 14, 2004
August 1, 2008
128 130 132 134 136

May 20, 2012
March 9, 2016
December 26, 2019
October 14, 2023
August 2, 2027
138 140 142 144 146

May 21, 2031
March 9, 2035
December 26, 2038
October 14, 2042
August 2, 2046
148 150 152 154 156

May 20, 2050
March 9, 2054
December 26, 2057
October 13, 2061
August 2, 2065
158 160 162 164 166

May 20, 2069		 March 8, 2073 December 26, 2076 October 13, 2080 August 1, 2084

Inex series

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.

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

References
  1. 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. "Annular Solar Eclipse of 2012 May 20". NASA Goddard Space Flight Center Eclipse Website. NASA. May 20, 2012. Retrieved May 20, 2012.
  3. "Eclipse Map - May 20–21 Solar Eclipse". TimeandDate.com. 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". Space.com. 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. Note S1: Eclipses & Predictions in Freeth, Tony (2014). "Eclipse Prediction on the Ancient Greek Astronomical Calculating Machine Known as the Antikythera Mechanism". PLOS ONE. 9 (7): e103275. Bibcode:2014PLoSO...9j3275F. doi:10.1371/journal.pone.0103275. PMC 4116162. PMID 25075747.
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