Solar eclipse of April 19, 1958

{{Infobox solar eclipse|1958Apr19

| previous = Solar eclipse of October 23, 1957

| next = Solar eclipse of October 12, 1958

}}

An annular solar eclipse occurred at the Moon's descending node of orbit on Saturday, April 19, 1958,{{cite web|title=April 19, 1958 Annular Solar Eclipse|url=https://www.timeanddate.com/eclipse/solar/1958-april-19|publisher=timeanddate|access-date=6 August 2024}} with a magnitude of 0.9408. 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 2.2 days after apogee (on April 16, 1958, at 22:40 UTC), the Moon's apparent diameter was smaller.{{cite web|title=Moon Distances for London, United Kingdom, England|url=https://www.timeanddate.com/astronomy/moon/distance.html?year=1958&n=136|publisher=timeanddate|access-date=6 August 2024}}

Annularity was visible in the Maldives, Nicobar Islands, Burma, Thailand including the capital city Bangkok, Cambodia, Laos, North Vietnam and South Vietnam (now belonging to Vietnam), China, British Hong Kong, Taiwan, Ryukyu Islands and Japan. Places east of International Date line witnessed the eclipse on April 18 (Friday). A partial eclipse was visible for most of Asia.

This was the last of four central solar eclipses visible from Bangkok from 1948 to 1958, where it is extremely rare for a large city to witness four central solar eclipses within 10 years.

Observation

Compared with a total solar eclipse, the chromosphere, corona and solar 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.{{cite journal|author=Н. А. Аменицкий, 李征帆, А. Е. Саломонович, У. В. Хангильдин, 陳鈞量|date=June 1959|title=1958年4月19日日环食时8毫米太阳射电观测|journal=天文学报 (Acta Astronomica Sinica)|volume=7|issue=1|pages=7–10}}

= China =

A joint observation team formed by the Academy of Sciences of the Soviet Union (predecessor of today's Russian Academy of Sciences) and the Chinese Academy of Sciences conducted 8-millimeter radio observation in Sanya, Hainan Island, China using the equatorial parabolic radio telescope manufactured by the Lebedev Physical Institute and the dual-channel radiometer as a receiver.{{cite web |title=Кольцеобразное солнечное затмение 19 апреля 1958 года |url=http://www.eclipse-2008.ru/eclipse/1958.php|archiveurl=https://web.archive.org/web/20090810164446/http://eclipse-2008.ru/eclipse/1958.php |archivedate=10 August 2009}} Radio astronomy started to develop from then in China.{{cite journal|author=储姗姗|year=2013|title=1958年中苏海南岛日食观测与中国射电天文学的开端|journal=2013中国天文学会学术年会文集}} Due to the Sino-Soviet split soon after this eclipse, the two countries did not conduct any joint observations of the total solar eclipse of September 22, 1968. On January 23, 1969, the People'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.{{cite news|title=用毛泽东思想探索太阳的奥秘——记我国首次大规模日全食综合观测队|work=People's Daily|date=23 January 1969|quote=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。}}

= Japan =

Observation ships were sent to Hachijō-jima, Izu Islands, Japan.{{cite web|title=トカラ列島を中心に長い金環日食|url=http://eclipse-navi.com/ichiran/nendai/1900to1999/1958.html|publisher=日食ナビ|archive-date=5 March 2016|archive-url=https://web.archive.org/web/20160305192234/http://eclipse-navi.com/ichiran/nendai/1900to1999/1958.html}} Pictures were also taken in Tanegashima, 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.{{cite web|title=1958年(昭和33年)の金環日食|url=http://blog.ktk.main.jp/?eid=896242|publisher=鹿児島県天文協会 (Kagoshima Prefecture Astronomical Association)|archive-date=4 March 2016|archive-url=https://web.archive.org/web/20160304112249/http://blog.ktk.main.jp/?eid=896242}}

Eclipse details

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.{{cite web|title=Annular Solar Eclipse of 1958 Apr 19|url=https://eclipsewise.com/solar/SEprime/1901-2000/SE1958Apr19Aprime.html|publisher=EclipseWise.com|access-date=6 August 2024}}

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|+April 19, 1958 Solar Eclipse Times

! 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

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|+April 19, 1958 Solar Eclipse Parameters

! 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

Eclipse season

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. The first and last eclipse in this sequence is separated by one synodic month.

class="wikitable"

|+ Eclipse season of April–May 1958

! April 4
Ascending node (full moon) !! April 19
Descending node (new moon)
!! May 3
Ascending node (full moon)

200px

align=center

| Penumbral lunar eclipse
Lunar Saros 102

Annular solar eclipse
Solar Saros 128

Partial lunar eclipse
Lunar Saros 140