View source for Solar eclipse of September 22, 1968

{{Short description|Total eclipse}}
{{Infobox solar eclipse|1968Sep22
| previous         = Solar eclipse of March 28, 1968
| next             = Solar eclipse of March 18, 1969
}}
A total [[solar eclipse]] occurred at the Moon's [[Lunar node|descending node]] of orbit on Sunday, September 22, 1968,<ref>{{cite web|title=September 22, 1968 Total Solar Eclipse|url=https://www.timeanddate.com/eclipse/solar/1968-september-22|publisher=timeanddate|access-date=8 August 2024}}</ref> with a [[Magnitude of eclipse|magnitude]] of 1.0099. 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. A total solar eclipse occurs when the Moon's [[apparent diameter]] is larger than the Sun's, blocking all direct sunlight, turning day into darkness. Totality occurs in a narrow path across Earth's surface, with the partial solar eclipse visible over a surrounding region thousands of kilometres wide. Occurring about 3.4 days before [[Apsis|perigee]] (on September 25, 1968, at 21:20 UTC), the Moon's apparent diameter was larger.<ref>{{cite web|title=Moon Distances for London, United Kingdom, England|url=https://www.timeanddate.com/astronomy/moon/distance.html?year=1968&n=136|publisher=timeanddate|access-date=8 August 2024}}</ref>

Totality was visible from the [[Soviet Union]] (today's [[Russia]] and [[Kazakhstan]]) and [[Xinjiang]] in [[Northwestern China]]. A partial eclipse was visible for parts of [[Europe]], [[Northeast Africa]], [[West Asia]], [[Central Asia]], and [[South Asia]].

== Observation ==
=== Soviet Union ===
A company named Opton proposed to the [[Sternberg Astronomical Institute]] to observe this solar eclipse in [[Sary Shagan]] on the west bank of [[Lake Balkhash]], and also wrote to the Soviet Ministry of Railways for help to get to the destination faster. The observation team obtained [[spectrum]] of the [[stellar corona|corona]]. Students also assisted in taking pictures of the corona with [[:ru:МТО (объектив)|MTO-1000]] lens.<ref>{{cite web |title=Полное солнечное затмение 22 сентября 1968 г. |url=http://www.eclipse-2008.ru/eclipse/1968.php |archiveurl=https://web.archive.org/web/20100103164731/http://eclipse-2008.ru/eclipse/1968.php |archivedate=3 January 2010}}</ref>

=== China ===
This is the first total solar eclipse visible in the country since the [[founding of the People's Republic of China]]. It occurred during the [[Cultural Revolution]], when astronomers including [[Zhang Yuzhe]] who organized observations of the total [[solar eclipse of June 19, 1936]] and [[solar eclipse of September 21, 1941|September 21, 1941]] were excluded from key positions. The [[Chinese Academy of Sciences]] sent a team of 200 including Zhang Kuisan (张魁三), the then deputy director of the Geophysics Bureau to Xinjiang. The observation was code-named "532", named after the time February 1953 when [[Mao Zedong]] visited the [[Purple Mountain Observatory]] in [[Nanjing]]. The travel to [[Ürümqi]] by train first took 3 days, and another 7 days by car to the optical observation site Zhaosu Town (Mongolküre Town), [[Zhaosu County]] and the radio observation site [[Kashgar]]. Gravity measurements were also conducted in mountain caves. In order to avoid the turmoil of the Cultural Revolution, [[Zhou Enlai]] sent [[:zh:劉西堯|Liu Xiyao]] to lead the army to the local area and provide the whole team with meals and accommodation. The observation team completed the first monochromatic light observation and high-resolution radio observation of the sun in China. This was also the first time in China that a solar eclipse was observed by plane. Shanghai Scientific and Educational Film Studio also produced a science and education film of the total solar eclipse.<ref>{{cite web|title=20世纪中国日全食观测小史|date=16 July 2009 |url=http://news.163.com/09/0716/14/5EBNGC9P00013H9Q.html|archive-date=17 October 2020|archive-url=https://web.archive.org/web/20201017233253/http://news.163.com/09/0716/14/5EBNGC9P00013H9Q.html}}</ref><ref>{{cite web|title=《新闻调查》 19970314 寻踪日全食|url=http://tv.cntv.cn/video/C10435/3d420a0300054dbf923455d9258823d5|publisher=[[China Network Television]]|archive-date=10 July 2015|archive-url=https://web.archive.org/web/20150710172617/http://tv.cntv.cn/video/C10435/3d420a0300054dbf923455d9258823d5}}</ref>

The Soviet Union and China were the only two countries the path of this total solar eclipse passed. Due to the [[Sino-Soviet split]], the two countries did not conduct any joint observations. About half a year after the eclipse, on January 23, 1969, the [[People's Daily]] published an article claiming that the observation of this eclipse "achieved brilliant results", repeatedly criticized the Soviet Union of "obstructing" it, and also mentioned that the Soviet Union "plundered data" of the annular [[solar eclipse of April 19, 1958]].<ref>{{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。}}</ref><ref>{{cite news|title=我国大规模日全食综合观测取得辉煌成果|work=[[People's Daily]]|date=23 January 1969}}</ref>

== 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.<ref>{{cite web|title=Total Solar Eclipse of 1968 Sep 22|url=https://eclipsewise.com/solar/SEprime/1901-2000/SE1968Sep22Tprime.html|publisher=EclipseWise.com|access-date=8 August 2024}}</ref>

{| class="wikitable" align="{{{align|left}}}" style="margin:{{#ifeq:{{{align}}}|left|0 0 0.5em 1em|0 1em 0.5em 0}}"
|+September 22, 1968 Solar Eclipse Times
! Event
! Time (UTC)
|-
| First Penumbral External Contact
| 1968 September 22 at 09:07:22.9 UTC
|-
| Equatorial Conjunction
| 1968 September 22 at 10:22:09.4 UTC
|-
| First Umbral External Contact
| 1968 September 22 at 10:44:14.2 UTC
|-
| First Central Line
| 1968 September 22 at 10:44:37.1 UTC
|-
| First Umbral Internal Contact
| 1968 September 22 at 10:45:00.3 UTC
|-
| Ecliptic Conjunction
| 1968 September 22 at 11:08:44.2 UTC
|-
| Greatest Eclipse
| 1968 September 22 at 11:18:46.0 UTC
|-
| Greatest Duration
| 1968 September 22 at 11:20:13.7 UTC
|-
| Last Umbral Internal Contact
| 1968 September 22 at 11:53:04.0 UTC
|-
| Last Central Line
| 1968 September 22 at 11:53:29.7 UTC
|-
| Last Umbral External Contact
| 1968 September 22 at 11:53:55.1 UTC
|-
| Last Penumbral External Contact
| 1968 September 22 at 13:30:26.7 UTC
|}

{|class="wikitable" align="{{{align|right}}}" style="margin:{{#ifeq:{{{align}}}|right|0 0 0.5em 1em|0 1em 0.5em 0}}"
|+September 22, 1968 Solar Eclipse Parameters
! Parameter
! Value
|-
| Eclipse Magnitude
| 1.00990
|-
| Eclipse Obscuration
| 1.01989
|-
| Gamma
| 0.94507
|-
| Sun Right Ascension
| 11h58m11.0s
|-
| Sun Declination
| +00°11'49.6"
|-
| Sun Semi-Diameter
| 15'56.3"
|-
| Sun Equatorial Horizontal Parallax
| 08.8"
|-
| Moon Right Ascension
| 11h59m58.7s
|-
| Moon Declination
| +01°00'16.0"
|-
| Moon Semi-Diameter
| 16'01.1"
|-
| Moon Equatorial Horizontal Parallax
| 0°58'47.3"
|-
| ΔT
| 38.9 s
|}
{{clear}}

== Eclipse season ==
{{See also|Eclipse cycle}}
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]].

{| class="wikitable"
|+ Eclipse season of September–October 1968
! September 22<br/>Descending node (new moon)<br/> !! [[October 1968 lunar eclipse|October 6]]<br/>Ascending node (full moon)<br/>
|-
| [[File:SE1968Sep22T.png|200px]] || [[File:Lunar eclipse chart close-1968Oct06.png|200px]]
|- align=center
| [[Total eclipse#Types|Total solar eclipse]]<br />Solar Saros 124 || [[Lunar eclipse#Types of lunar eclipse|Total lunar eclipse]]<br />Lunar Saros 136
|}

== Related eclipses ==
=== Eclipses in 1968 ===
* [[Solar eclipse of March 28, 1968|A partial solar eclipse on March 28]].
* [[April 1968 lunar eclipse|A total lunar eclipse on April 13]].
* '''A total solar eclipse on September 22.'''
* [[October 1968 lunar eclipse|A total lunar eclipse on October 6]].

=== Metonic ===
* Preceded by: [[Solar eclipse of December 4, 1964]]
* Followed by: [[Solar eclipse of July 10, 1972]]

=== Tzolkinex ===
* Preceded by: [[Solar eclipse of August 11, 1961]]
* Followed by: [[Solar eclipse of November 3, 1975]]

=== Half-Saros ===
* Preceded by: [[September 1959 lunar eclipse|Lunar eclipse of September 17, 1959]]
* Followed by: [[September 1977 lunar eclipse|Lunar eclipse of September 27, 1977]]

=== Tritos ===
* Preceded by: [[Solar eclipse of October 23, 1957]]
* Followed by: [[Solar eclipse of August 22, 1979]]

=== Solar Saros 124 ===
* Preceded by: [[Solar eclipse of September 12, 1950]]
* Followed by: [[Solar eclipse of October 3, 1986]]

=== Inex ===
* Preceded by: [[Solar eclipse of October 12, 1939]]
* Followed by: [[Solar eclipse of September 2, 1997]]

=== Triad ===
* Preceded by: [[Solar eclipse of November 21, 1881]]
* Followed by: [[Solar eclipse of July 24, 2055]]

=== Solar eclipses of 1968–1971 ===
{{Solar eclipse set 1968–1971}}

=== Saros 124 ===
{{Solar Saros series 124}}

=== Metonic series ===
{{Solar Metonic series 1953–2029}}

=== Tritos series ===
{{Solar Tritos series 2001 June 21}}

=== Inex series ===
{{Solar Inex series 2026 August 12}}

==References==
{{reflist}}

==External links==
{{Solar eclipse NASA reference|1951/SE1968Sep22T|19680922}}
* [https://web.archive.org/web/20100103164731/http://eclipse-2008.ru/eclipse/1968.php Photos from solar eclipse of September 22, 1968 in USSR] (Russian)

{{Solar eclipses}}
{{Commons category}}

{{DEFAULTSORT:Solar Eclipse Of September 22, 1968}}
[[Category:Total solar eclipses|1968 09 22]]
[[Category:1968 in science]]
[[Category:20th-century solar eclipses|1968 09 22]]
[[Category:September 1968]]