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Solar eclipse of September 23, 1987

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Solar eclipse of September 23, 1987
Map
Type of eclipse
NatureAnnular
Gamma0.2787
Magnitude0.9634
Maximum eclipse
Duration229 s (3 min 49 s)
Coordinates14°18′N 138°24′E / 14.3°N 138.4°E / 14.3; 138.4
Max. width of band137 km (85 mi)
Times (UTC)
Greatest eclipse3:12:22
References
Saros134 (42 of 71)
Catalog # (SE5000)9481

An annular solar eclipse occurred at the Moon's descending node of orbit on Wednesday, September 23, 1987,[1] with a magnitude of 0.9634. A solar eclipse 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. Occurring only 5 days after apogee (on September 18, 1987, at 4:00 UTC), the Moon's apparent diameter was smaller.[2]

Annularity was visible in the Soviet Union (today's Kazakhstan), China (including Shanghai), southwestern Mongolia, Okinawa Islands of Japan except Kume Island and the southwestern tip of Kerama Islands, the Federal States of Micronesia, Papua New Guinea, Solomon Islands, Rotuma Islands of Fiji, Wallis Islands and West Samoa (the name changed to Samoa later). A partial eclipse was visible for parts of South Asia, Southeast Asia, East Asia, Australia, Oceania, and Hawaii.

Observation

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Five radio observation stations were present in China at the time of the eclipse, two of which were within the annularity, in Ürümqi and Shanghai respectively. A partial solar eclipse was observed from the other three, including one in Nanjing where the eclipse was close to annularity, and the rest two in Beijing and Kunming. The Department of Mathematics and Physics of the Chinese Academy of Sciences and the Chinese Astronomical Society held a meeting in Kunming in December 1986, deciding that on-site observation would be conducted at each station, among which the Shanghai Astronomical Observatory was considered to have the best location with a larger magnitude of the eclipse, longer duration and larger solar zenith angle. The Shanghai Astronomical Observatory conducted observations with seven different wave bands using a 25-metre radio telescope.[3] The Yunnan Astronomical Observatory located in Kunming also conducted a multi-band joint observation of the partial solar eclipse.[4]

The Chinese Research Institute of Radio Wave Propagation conducted observations with a high-frequency skywave radar located in Xinxiang on the southern limit of annularity. Uneven structure and motion were observed in the ionosphere, the highest operating frequency was found changed during the eclipse, and large-scale fluctuations continued after the eclipse.[5]

Eclipse details

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Shown below are two tables displaying details about this particular solar eclipse. The first table outlines times at which the moon's penumbra or umbra attains the specific parameter, and the second table describes various other parameters pertaining to this eclipse.[6]

September 23, 1987 Solar Eclipse Times
Event Time (UTC)
First Penumbral External Contact 1987 September 23 at 00:15:50.5 UTC
First Umbral External Contact 1987 September 23 at 01:20:19.5 UTC
First Central Line 1987 September 23 at 01:22:07.2 UTC
First Umbral Internal Contact 1987 September 23 at 01:23:55.0 UTC
First Penumbral Internal Contact 1987 September 23 at 02:33:48.6 UTC
Greatest Duration 1987 September 23 at 02:45:44.7 UTC
Equatorial Conjunction 1987 September 23 at 02:54:28.0 UTC
Ecliptic Conjunction 1987 September 23 at 03:09:08.4 UTC
Greatest Eclipse 1987 September 23 at 03:12:21.6 UTC
Last Penumbral Internal Contact 1987 September 23 at 03:51:20.8 UTC
Last Umbral Internal Contact 1987 September 23 at 05:01:01.1 UTC
Last Central Line 1987 September 23 at 05:02:46.3 UTC
Last Umbral External Contact 1987 September 23 at 05:04:31.2 UTC
Last Penumbral External Contact 1987 September 23 at 06:08:54.0 UTC
September 23, 1987 Solar Eclipse Parameters
Parameter Value
Eclipse Magnitude 0.96337
Eclipse Obscuration 0.92807
Gamma 0.27869
Sun Right Ascension 11h58m25.1s
Sun Declination +00°10'17.1"
Sun Semi-Diameter 15'56.2"
Sun Equatorial Horizontal Parallax 08.8"
Moon Right Ascension 11h58m55.2s
Moon Declination +00°23'45.5"
Moon Semi-Diameter 15'07.6"
Moon Equatorial Horizontal Parallax 0°55'30.9"
ΔT 55.7 s

Eclipse season

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This eclipse is part of an eclipse season, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by a fortnight.

Eclipse season of September–October 1987
September 23
Descending node (new moon)
October 7
Ascending node (full moon)
Annular solar eclipse
Solar Saros 134
Penumbral lunar eclipse
Lunar Saros 146
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Eclipses in 1987

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Metonic

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Tzolkinex

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Half-Saros

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Tritos

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Solar Saros 134

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Inex

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Triad

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Solar eclipses of 1986–1989

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This eclipse is a member of a 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.[7]

Solar eclipse series sets from 1986 to 1989
Ascending node   Descending node
Saros Map Gamma Saros Map Gamma
119 April 9, 1986

Partial
−1.0822 124 October 3, 1986

Hybrid
0.9931
129 March 29, 1987

Hybrid
−0.3053 134 September 23, 1987

Annular
0.2787
139 March 18, 1988

Total
0.4188 144 September 11, 1988

Annular
−0.4681
149 March 7, 1989

Partial
1.0981 154 August 31, 1989

Partial
−1.1928

Saros 134

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This eclipse is a part of Saros series 134, repeating every 18 years, 11 days, and containing 71 events. The series started with a partial solar eclipse on June 22, 1248. It contains total eclipses from October 9, 1428 through December 24, 1554; hybrid eclipses from January 3, 1573 through June 27, 1843; and annular eclipses from July 8, 1861 through May 21, 2384. The series ends at member 72 as a partial eclipse on August 6, 2510. Its eclipses are tabulated in three columns; every third eclipse in the same column is one exeligmos apart, so they all cast shadows over approximately the same parts of the Earth.

The longest duration of totality was produced by member 11 at 1 minutes, 30 seconds on October 9, 1428, and the longest duration of annularity will be produced by member 52 at 10 minutes, 55 seconds on January 10, 2168. All eclipses in this series occur at the Moon’s descending node of orbit.[8]

Series members 32–53 occur between 1801 and 2200:
32 33 34

June 6, 1807

June 16, 1825

June 27, 1843
35 36 37

July 8, 1861

July 19, 1879

July 29, 1897
38 39 40

August 10, 1915

August 21, 1933

September 1, 1951
41 42 43

September 11, 1969

September 23, 1987

October 3, 2005
44 45 46

October 14, 2023

October 25, 2041

November 5, 2059
47 48 49

November 15, 2077

November 27, 2095

December 8, 2113
50 51 52

December 19, 2131

December 30, 2149

January 10, 2168
53

January 20, 2186

Metonic series

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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.

21 eclipse events between July 11, 1953 and July 11, 2029
July 10–11 April 29–30 February 15–16 December 4 September 21–23
116 118 120 122 124

July 11, 1953

April 30, 1957

February 15, 1961

December 4, 1964

September 22, 1968
126 128 130 132 134

July 10, 1972

April 29, 1976

February 16, 1980

December 4, 1983

September 23, 1987
136 138 140 142 144

July 11, 1991

April 29, 1995

February 16, 1999

December 4, 2002

September 22, 2006
146 148 150 152 154

July 11, 2010

April 29, 2014

February 15, 2018

December 4, 2021

September 21, 2025
156

July 11, 2029

Tritos series

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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.

Series members between 1801 and 2200

March 4, 1802
(Saros 117)

February 1, 1813
(Saros 118)

January 1, 1824
(Saros 119)

November 30, 1834
(Saros 120)

October 30, 1845
(Saros 121)

September 29, 1856
(Saros 122)

August 29, 1867
(Saros 123)

July 29, 1878
(Saros 124)

June 28, 1889
(Saros 125)

May 28, 1900
(Saros 126)

April 28, 1911
(Saros 127)

March 28, 1922
(Saros 128)

February 24, 1933
(Saros 129)

January 25, 1944
(Saros 130)

December 25, 1954
(Saros 131)

November 23, 1965
(Saros 132)

October 23, 1976
(Saros 133)

September 23, 1987
(Saros 134)

August 22, 1998
(Saros 135)

July 22, 2009
(Saros 136)

June 21, 2020
(Saros 137)

May 21, 2031
(Saros 138)

April 20, 2042
(Saros 139)

March 20, 2053
(Saros 140)

February 17, 2064
(Saros 141)

January 16, 2075
(Saros 142)

December 16, 2085
(Saros 143)

November 15, 2096
(Saros 144)

October 16, 2107
(Saros 145)

September 15, 2118
(Saros 146)

August 15, 2129
(Saros 147)

July 14, 2140
(Saros 148)

June 14, 2151
(Saros 149)

May 14, 2162
(Saros 150)

April 12, 2173
(Saros 151)

March 12, 2184
(Saros 152)

February 10, 2195
(Saros 153)

Inex series

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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.

Series members between 1801 and 2200

January 21, 1814
(Saros 128)

December 31, 1842
(Saros 129)

December 12, 1871
(Saros 130)

November 22, 1900
(Saros 131)

November 1, 1929
(Saros 132)

October 12, 1958
(Saros 133)

September 23, 1987
(Saros 134)

September 1, 2016
(Saros 135)

August 12, 2045
(Saros 136)

July 24, 2074
(Saros 137)

July 4, 2103
(Saros 138)

June 13, 2132
(Saros 139)

May 25, 2161
(Saros 140)

May 4, 2190
(Saros 141)

Notes

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  1. ^ "September 23, 1987 Annular Solar Eclipse". timeanddate. Retrieved 9 August 2024.
  2. ^ "Moon Distances for London, United Kingdom, England". timeanddate. Retrieved 9 August 2024.
  3. ^ 纪树臣 季德盛 梁世光 (1988). "1987年9月23日沪台25米天线观测选题及方案". 云南天文台台刊 (4): 100–105.
  4. ^ 纪树臣 杨荣邦 谢瑞祥 (1989). "1987年9月23日日偏食云台多波段联合观测". 云南天文台台刊 (3): 46–53.
  5. ^ 焦培南 (1990). "1987年9月23日日环食的电离层波动现象". 地球物理学报. 33 (4): 391–398. Archived from the original on 21 July 2015.
  6. ^ "Annular Solar Eclipse of 1987 Sep 23". EclipseWise.com. Retrieved 9 August 2024.
  7. ^ 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.
  8. ^ "NASA - Catalog of Solar Eclipses of Saros 134". eclipse.gsfc.nasa.gov.

References

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