| Annular eclipse | |
 Map | |
| Gamma | 0.275 |
|---|---|
| Magnitude | 0.9408 |
| Maximum eclipse | |
| Duration | 427 s (7 min 7 s) |
| Coordinates | 26°30′N123°36′E / 26.5°N 123.6°E /26.5; 123.6 |
| Max. width of band | 228 km (142 mi) |
| Times (UTC) | |
| Greatest eclipse | 3:27:17 |
| References | |
| Saros | 128 (55 of 73) |
| Catalog # (SE5000) | 9416 |
An annularsolar eclipse occurred at the Moon'sdescending node of orbit on Saturday, April 19, 1958,[1] with amagnitude of 0.9408. Asolar eclipse occurs when theMoon passes betweenEarth and theSun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. An annular solar eclipse occurs when the Moon'sapparent diameter is smaller than the Sun's, blocking most of the Sun's light and causing the Sun to look like anannulus (ring). An annular eclipse appears as a partial eclipse over a region of the Earth thousands of kilometres wide. Occurring about 2.2 days afterapogee (on April 16, 1958, at 22:40 UTC), the Moon's apparent diameter was smaller.[2]
Annularity was visible in theMaldives,Nicobar Islands,Burma,Thailand including the capital cityBangkok,Cambodia,Laos,North Vietnam andSouth Vietnam (now belonging toVietnam),China,British Hong Kong,Taiwan,Ryukyu Islands andJapan. Places east of International Date line witnessed the eclipse on April 18 (Friday). A partial eclipse was visible for most ofAsia.
This was the last of four central solar eclipses visible from Bangkok from1948 to 1958, where it is extremely rare for a large city to witness four central solar eclipses within 10 years.
Compared with a total solar eclipse, thechromosphere,corona andsolar prominence are invisible during an annular eclipse. However, observations of millimeter-wave solar radio can provide data for lower- and mid-layer structure of the chromosphere, which is more valuable during an annular solar eclipse.[3]
A joint observation team formed by theAcademy of Sciences of the Soviet Union (predecessor of today'sRussian Academy of Sciences) and theChinese Academy of Sciences conducted 8-millimeter radio observation inSanya,Hainan Island, China using the equatorial parabolicradio telescope manufactured by theLebedev Physical Institute and the dual-channel radiometer as a receiver.[3][4]Radio astronomy started to develop from then in China.[5] Due to theSino-Soviet split soon after this eclipse, the two countries did not conduct any joint observations of the totalsolar eclipse of September 22, 1968. On January 23, 1969, thePeople's Daily published an article reporting the observation of the eclipse in 1968, where it also criticized that the Soviet Union "plundered data of the annular solar eclipse" in 1958, only left China a "worn radio telescope antenna", and later even asked for it back.[6]
Observation ships were sent toHachijō-jima,Izu Islands, Japan.[7] Pictures were also taken inTanegashima,Osumi Islands, and luminosity, air pressure, temperature, humidity, water temperature of the storage tank, ground temperature, wind direction, wind speed and other data were recorded every 10 minutes.[8]
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.[9]
| Event | Time (UTC) |
|---|---|
| First Penumbral External Contact | 1958 April 19 at 00:24:41.6 UTC |
| First Umbral External Contact | 1958 April 19 at 01:30:53.9 UTC |
| First Central Line | 1958 April 19 at 01:33:33.8 UTC |
| First Umbral Internal Contact | 1958 April 19 at 01:36:14.1 UTC |
| First Penumbral Internal Contact | 1958 April 19 at 02:47:56.9 UTC |
| Ecliptic Conjunction | 1958 April 19 at 03:23:59.6 UTC |
| Greatest Eclipse | 1958 April 19 at 03:27:16.7 UTC |
| Greatest Duration | 1958 April 19 at 03:33:53.0 UTC |
| Equatorial Conjunction | 1958 April 19 at 03:36:02.5 UTC |
| Last Penumbral Internal Contact | 1958 April 19 at 04:06:22.2 UTC |
| Last Umbral Internal Contact | 1958 April 19 at 05:18:13.8 UTC |
| Last Central Line | 1958 April 19 at 05:20:52.8 UTC |
| Last Umbral External Contact | 1958 April 19 at 05:23:31.5 UTC |
| Last Penumbral External Contact | 1958 April 19 at 06:29:44.7 UTC |
| Parameter | Value |
|---|---|
| Eclipse Magnitude | 0.94082 |
| Eclipse Obscuration | 0.88515 |
| Gamma | 0.27499 |
| Sun Right Ascension | 01h46m12.4s |
| Sun Declination | +10°58'10.3" |
| Sun Semi-Diameter | 15'55.4" |
| Sun Equatorial Horizontal Parallax | 08.8" |
| Moon Right Ascension | 01h45m56.6s |
| Moon Declination | +11°12'31.2" |
| Moon Semi-Diameter | 14'45.9" |
| Moon Equatorial Horizontal Parallax | 0°54'11.2" |
| ΔT | 32.3 s |
This eclipse is part of aneclipse 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 afortnight. The first and last eclipse in this sequence is separated by onesynodic month.
| April 4 Ascending node (full moon) | April 19 Descending node (new moon) | May 3 Ascending node (full moon) |
|---|---|---|
 | |  |
| Penumbral lunar eclipse Lunar Saros 102 | Annular solar eclipse Solar Saros 128 | Partial lunar eclipse Lunar Saros 140 |
This eclipse is a member of asemester series. An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodes of the Moon's orbit.[10]
| Solar eclipse series sets from 1957 to 1960 | ||||||
|---|---|---|---|---|---|---|
| Descending node | Ascending node | |||||
| Saros | Map | Gamma | Saros | Map | Gamma | |
| 118 | April 30, 1957 Annular (non-central) | 0.9992 | 123 | October 23, 1957 Total (non-central) | 1.0022 | |
| 128 | April 19, 1958 Annular | 0.275 | 133 | October 12, 1958 Total | −0.2951 | |
| 138 | April 8, 1959 Annular | −0.4546 | 143 | October 2, 1959 Total | 0.4207 | |
| 148 | March 27, 1960 Partial | −1.1537 | 153 | September 20, 1960 Partial | 1.2057 | |
This eclipse is a part ofSaros series 128, repeating every 18 years, 11 days, and containing 73 events. The series started with a partial solar eclipse on August 29, 984 AD. It contains total eclipses from May 16, 1417 through June 18, 1471; hybrid eclipses from June 28, 1489 through July 31, 1543; and annular eclipses from August 11, 1561 through July 25, 2120. The series ends at member 73 as a partial eclipse on November 1, 2282. Its eclipses are tabulated in three columns; every third eclipse in the same column is oneexeligmos apart, so they all cast shadows over approximately the same parts of the Earth.
The longest duration of totality was produced by member 27 at 1 minutes, 45 seconds on June 7, 1453, and the longest duration of annularity was produced by member 48 at 8 minutes, 35 seconds on February 1, 1832. All eclipses in this series occur at the Moon’sdescending node of orbit.[11]
| Series members 47–68 occur between 1801 and 2200: | ||
|---|---|---|
| 47 | 48 | 49 |
 January 21, 1814 |  February 1, 1832 |  February 12, 1850 |
| 50 | 51 | 52 |
 February 23, 1868 |  March 5, 1886 |  March 17, 1904 |
| 53 | 54 | 55 |
 March 28, 1922 |  April 7, 1940 | April 19, 1958 |
| 56 | 57 | 58 |
 April 29, 1976 |  May 10, 1994 |  May 20, 2012 |
| 59 | 60 | 61 |
 June 1, 2030 |  June 11, 2048 |  June 22, 2066 |
| 62 | 63 | 64 |
 July 3, 2084 |  July 15, 2102 |  July 25, 2120 |
| 65 | 66 | 67 |
 August 5, 2138 |  August 16, 2156 |  August 27, 2174 |
| 68 | ||
 September 6, 2192 | ||
Themetonic 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.
| 22 eclipse events between September 12, 1931 and July 1, 2011 | ||||
|---|---|---|---|---|
| September 11–12 | June 30–July 1 | April 17–19 | February 4–5 | November 22–23 |
| 114 | 116 | 118 | 120 | 122 |
 September 12, 1931 |  June 30, 1935 |  April 19, 1939 |  February 4, 1943 |  November 23, 1946 |
| 124 | 126 | 128 | 130 | 132 |
 September 12, 1950 |  June 30, 1954 | April 19, 1958 |  February 5, 1962 |  November 23, 1965 |
| 134 | 136 | 138 | 140 | 142 |
 September 11, 1969 |  June 30, 1973 |  April 18, 1977 |  February 4, 1981 |  November 22, 1984 |
| 144 | 146 | 148 | 150 | 152 |
 September 11, 1988 |  June 30, 1992 |  April 17, 1996 |  February 5, 2000 |  November 23, 2003 |
| 154 | 156 | |||
 September 11, 2007 |  July 1, 2011 | |||
This eclipse is a part of atritos cycle, repeating at alternating nodes every 135synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with theanomalistic 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 periodinex cycle, repeating at alternating nodes, every 358synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with theanomalistic 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 | ||
|---|---|---|
 July 27, 1813 (Saros 123) |  July 8, 1842 (Saros 124) |  June 18, 1871 (Saros 125) |
 May 28, 1900 (Saros 126) |  May 9, 1929 (Saros 127) | April 19, 1958 (Saros 128) |
 March 29, 1987 (Saros 129) |  March 9, 2016 (Saros 130) |  February 16, 2045 (Saros 131) |
 January 27, 2074 (Saros 132) |  January 8, 2103 (Saros 133) |  December 19, 2131 (Saros 134) |
 November 27, 2160 (Saros 135) |  November 8, 2189 (Saros 136) | |
{{cite journal}}: CS1 maint: multiple names: authors list (link)一九五八年苏修打着"中苏日环食联合观测"的幌子，来我国掠取日环食资料。观测结束后，把一台破烂不堪的射电望远镜天线留在中国，还美其名曰"帮助中国发展射电天文学"。后来，赫鲁晓夫修正主义集团把这个破烂的射电望远镜天线也要了回去。
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