Solar eclipse of July 20, 1925 (original) (raw)

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20th-century annular solar eclipse

Solar eclipse of July 20, 1925

Annular eclipse
Map
Gamma −0.7193
Magnitude 0.9436
Maximum eclipse
Duration 435 s (7 min 15 s)
Coordinates 25°18′S 150°00′W / 25.3°S 150°W / -25.3; -150
Max. width of band 300 km (190 mi)
Times (UTC)
Greatest eclipse 21:48:42
References
Saros 125 (49 of 73)
Catalog # (SE5000) 9340
← January 24, 1925January 14, 1926 →

An annular solar eclipse occurred at the Moon's ascending node of orbit between Monday, July 20 and Tuesday, July 21, 1925,[1] with a magnitude of 0.9436. 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 about 8 hours after apogee (on July 20, 1925, at 13:30 UTC), the Moon's apparent diameter was smaller.[2]

Annularity was visible from northern part of Northland Region and the whole Kermadec Islands in New Zealand on July 21 (Tuesday), and Rapa Iti in French Polynesia on July 20 (Monday). A partial eclipse was visible for parts of Eastern Australia and Oceania.

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.[3]

July 20, 1925 Solar Eclipse Times

Event Time (UTC)
First Penumbral External Contact 1925 July 20 at 19:03:41.7 UTC
First Umbral External Contact 1925 July 20 at 20:23:08.9 UTC
First Central Line 1925 July 20 at 20:26:27.5 UTC
First Umbral Internal Contact 1925 July 20 at 20:29:50.5 UTC
Ecliptic Conjunction 1925 July 20 at 21:40:09.2 UTC
Greatest Duration 1925 July 20 at 21:46:03.5 UTC
Greatest Eclipse 1925 July 20 at 21:48:41.6 UTC
Equatorial Conjunction 1925 July 20 at 21:57:08.7 UTC
Last Umbral Internal Contact 1925 July 20 at 23:07:26.9 UTC
Last Central Line 1925 July 20 at 23:10:49.8 UTC
Last Umbral External Contact 1925 July 20 at 23:14:08.3 UTC
Last Penumbral External Contact 1925 July 21 at 00:33:37.3 UTC

July 20, 1925 Solar Eclipse Parameters

Parameter Value
Eclipse Magnitude 0.94358
Eclipse Obscuration 0.89035
Gamma −0.71927
Sun Right Ascension 07h58m46.0s
Sun Declination +20°38'42.8"
Sun Semi-Diameter 15'44.4"
Sun Equatorial Horizontal Parallax 08.7"
Moon Right Ascension 07h58m29.8s
Moon Declination +20°00'11.9"
Moon Semi-Diameter 14'42.0"
Moon Equatorial Horizontal Parallax 0°53'57.1"
ΔT 23.7 s

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 July–August 1925

July 20Ascending node (new moon) August 4Descending node (full moon)
Annular solar eclipseSolar Saros 125 Partial lunar eclipseLunar Saros 137

Solar eclipses of 1924–1928

[edit]

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.[4]

The partial solar eclipses on March 5, 1924 and August 30, 1924 occur in the previous lunar year eclipse set, and the solar eclipses on May 19, 1928 and November 12, 1928 occur in the next lunar year eclipse set.

Solar eclipse series sets from 1924 to 1928
Ascending node Descending node
Saros Map Gamma Saros Map Gamma
115 July 31, 1924Partial −1.4459 120 January 24, 1925Total 0.8661
125 July 20, 1925Annular −0.7193 130Totality in Sumatra, Indonesia January 14, 1926Total 0.1973
135 July 9, 1926Annular 0.0538 140 January 3, 1927Annular −0.4956
145 June 29, 1927Total 0.8163 150 December 24, 1927Partial −1.2416
155 June 17, 1928Partial 1.5107

This eclipse is a part of Saros series 125, repeating every 18 years, 11 days, and containing 73 events. The series started with a partial solar eclipse on February 4, 1060. It contains total eclipses from June 13, 1276 through July 16, 1330; hybrid eclipses on July 26, 1348 and August 7, 1366; and annular eclipses from August 17, 1384 through August 22, 1979. The series ends at member 73 as a partial eclipse on April 9, 2358. 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 14 at 1 minutes, 11 seconds on June 25, 1294, and the longest duration of annularity was produced by member 48 at 7 minutes, 23 seconds on July 10, 1907. All eclipses in this series occur at the Moon’s ascending node of orbit.[5]

Series members 43–64 occur between 1801 and 2200:
43 44 45
May 16, 1817 May 27, 1835 June 6, 1853
46 47 48
June 18, 1871 June 28, 1889 July 10, 1907
49 50 51
July 20, 1925 August 1, 1943 August 11, 1961
52 53 54
August 22, 1979 September 2, 1997 September 13, 2015
55 56 57
September 23, 2033 October 4, 2051 October 15, 2069
58 59 60
October 26, 2087 November 6, 2105 November 18, 2123
61 62 63
November 28, 2141 December 9, 2159 December 20, 2177
64
December 31, 2195

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 ascending node.

22 eclipse events between December 13, 1898 and July 20, 1982
December 13–14 October 1–2 July 20–21 May 9 February 24–25
111 113 115 117 119
December 13, 1898 July 21, 1906 May 9, 1910 February 25, 1914
121 123 125 127 129
December 14, 1917 October 1, 1921 July 20, 1925 May 9, 1929 February 24, 1933
131 133 135 137 139
December 13, 1936 October 1, 1940 July 20, 1944 May 9, 1948 February 25, 1952
141 143 145 147 149
December 14, 1955 October 2, 1959 July 20, 1963 May 9, 1967 February 25, 1971
151 153 155
December 13, 1974 October 2, 1978 July 20, 1982

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
June 26, 1805(Saros 114) May 27, 1816(Saros 115) April 26, 1827(Saros 116) March 25, 1838(Saros 117) February 23, 1849(Saros 118)
January 23, 1860(Saros 119) December 22, 1870(Saros 120) November 21, 1881(Saros 121) October 20, 1892(Saros 122) September 21, 1903(Saros 123)
August 21, 1914(Saros 124) July 20, 1925(Saros 125) June 19, 1936(Saros 126) May 20, 1947(Saros 127) April 19, 1958(Saros 128)
March 18, 1969(Saros 129) February 16, 1980(Saros 130) January 15, 1991(Saros 131) December 14, 2001(Saros 132) November 13, 2012(Saros 133)
October 14, 2023(Saros 134) September 12, 2034(Saros 135) August 12, 2045(Saros 136) July 12, 2056(Saros 137) June 11, 2067(Saros 138)
May 11, 2078(Saros 139) April 10, 2089(Saros 140) March 10, 2100(Saros 141) February 8, 2111(Saros 142) January 8, 2122(Saros 143)
December 7, 2132(Saros 144) November 7, 2143(Saros 145) October 7, 2154(Saros 146) September 5, 2165(Saros 147) August 4, 2176(Saros 148)
July 6, 2187(Saros 149) June 4, 2198(Saros 150)

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
October 9, 1809(Saros 121) September 18, 1838(Saros 122) August 29, 1867(Saros 123)
August 9, 1896(Saros 124) July 20, 1925(Saros 125) June 30, 1954(Saros 126)
June 11, 1983(Saros 127) May 20, 2012(Saros 128) April 30, 2041(Saros 129)
April 11, 2070(Saros 130) March 21, 2099(Saros 131) March 1, 2128(Saros 132)
February 9, 2157(Saros 133) January 20, 2186(Saros 134)
  1. ^ "July 20–21, 1925 Annular Solar Eclipse". timeanddate. Retrieved 2 August 2024.
  2. ^ "Moon Distances for London, United Kingdom, England". timeanddate. Retrieved 2 August 2024.
  3. ^ "Annular Solar Eclipse of 1925 Jul 20". EclipseWise.com. Retrieved 2 August 2024.
  4. ^ 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.
  5. ^ "NASA - Catalog of Solar Eclipses of Saros 125". eclipse.gsfc.nasa.gov.