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2025-03-03T06:18:18Z

Related eclipses

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{{short description|Partial lunar eclipse in 1921}}
{{Infobox lunar eclipse
| type = total
| image = Lunar eclipse chart close-1921Apr22.png
| caption = The Moon's hourly motion shown right to left
| date = April 22, 1921
| gamma = 0.4269
| magnitude = 1.0678
| saros_ser = 130
| saros_no = 29 of 72
| totality = 40 minutes, 7 seconds
| partiality = 202 minutes, 2 seconds
| penumbral = 331 minutes, 54 seconds
| p1 = 4:58:21
| u1 = 6:03:14
| u2 = 7:24:12
| greatest = 7:44:17
| u3 = 8:04:19
| u4 = 9:25:16
| p4 = 10:30:16
| previous = October 1920
| next = October 1921
}}
A total [[lunar eclipse]] occurred at the Moon’s [[Lunar node|ascending node]] of orbit on Friday, April 22, 1921,<ref>{{cite web|title=April 21–22, 1921 Total Lunar Eclipse (Blood Moon)|url=https://www.timeanddate.com/eclipse/lunar/1921-april-22|publisher=timeanddate|access-date=16 December 2024}}</ref> with an umbral [[Magnitude of eclipse|magnitude]] of 1.0678. A lunar eclipse occurs when the [[Moon]] moves into the [[Earth's shadow]], causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a [[solar eclipse]], which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the [[night]] side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's [[Umbra, penumbra and antumbra|shadow]] is smaller. Occurring only about 5.6 days after [[Apsis|perigee]] (on April 16, 1921, at 16:10 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=1921&n=136|publisher=timeanddate|access-date=16 December 2024}}</ref>

This lunar eclipse was the third of an [[Tetrad (astronomy)|almost tetrad]], with the others being on [[May 1920 lunar eclipse|May 3, 1920]] (total); [[October 1920 lunar eclipse|October 27, 1920]] (total); and [[October 1921 lunar eclipse|October 16, 1921]] (partial).

This was the first total lunar eclipse of [[Lunar Saros 130]].

== Visibility ==
The eclipse was completely visible over much of [[North America]] and western [[South America]], seen rising over [[northeast Asia]] and [[Australia]] and setting over eastern South America, [[western Europe]], and [[west Africa]].<ref>{{cite web|title=Total Lunar Eclipse of 1921 Apr 22|url=https://eclipse.gsfc.nasa.gov/LEplot/LEplot1901/LE1921Apr22T.pdf|publisher=NASA|access-date=16 December 2024}}</ref>

{| class=wikitable
|[[File:Lunar eclipse from moon-1921Apr22.png|300px]] [[File:Lunar eclipse chart close-1921Apr22.png|300px]]
|}

== Eclipse details ==
Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.<ref>{{cite web|title=Total Lunar Eclipse of 1921 Apr 22|url=https://eclipsewise.com/lunar/LEprime/1901-2000/LE1921Apr22Tprime.html|publisher=EclipseWise.com|access-date=16 December 2024}}</ref>

{|class="wikitable" align="{{{align|left}}}" style="margin:{{#ifeq:{{{align}}}|right|0 0 0.5em 1em|0 1em 0.5em 0}}"
|+April 22, 1921 Lunar Eclipse Parameters
! Parameter
! Value
|-
| Penumbral Magnitude
| 2.08154
|-
| Umbral Magnitude
| 1.06782
|-
| Gamma
| 0.42693
|-
| Sun Right Ascension
| 01h57m53.3s
|-
| Sun Declination
| +12°02'44.0"
|-
| Sun Semi-Diameter
| 15'54.4"
|-
| Sun Equatorial Horizontal Parallax
| 08.7"
|-
| Moon Right Ascension
| 13h58m18.6s
|-
| Moon Declination
| -11°38'56.5"
|-
| Moon Semi-Diameter
| 15'41.5"
|-
| Moon Equatorial Horizontal Parallax
| 0°57'35.3"
|-
| ΔT
| 22.2 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 April 1921
! [[Solar eclipse of April 8, 1921|April 8]] Descending node (new moon) !! April 22 Ascending node (full moon)
|-
| [[File:SE1921Apr08A.png|200px]] || [[File:Lunar eclipse chart close-1921Apr22.png|200px]]
|- align=center
| [[Total eclipse#Types|Annular solar eclipse]] Solar Saros 118 || [[Lunar eclipse#Types of lunar eclipse|Total lunar eclipse]] Lunar Saros 130
|}

== Related eclipses ==
=== Eclipses in 1921 ===
* [[Solar eclipse of April 8, 1921|An annular solar eclipse on April 8]].
* '''A total lunar eclipse on April 22.'''
* [[Solar eclipse of October 1, 1921|A total solar eclipse on October 1]].
* [[October 1921 lunar eclipse|A partial lunar eclipse on October 16]].

=== Metonic ===
* Preceded by: [[July 1917 lunar eclipse|Lunar eclipse of July 4, 1917]]
* Followed by: [[February 1925 lunar eclipse|Lunar eclipse of February 8, 1925]]

=== Tzolkinex ===
* Preceded by: [[March 1914 lunar eclipse|Lunar eclipse of March 12, 1914]]
* Followed by: [[June 1928 lunar eclipse|Lunar eclipse of June 3, 1928]]

=== Half-Saros ===
* Preceded by: [[Solar eclipse of April 17, 1912]]
* Followed by: [[Solar eclipse of April 28, 1930]]

=== Tritos ===
* Preceded by: [[May 1910 lunar eclipse|Lunar eclipse of May 24, 1910]]
* Followed by: [[March 1932 lunar eclipse|Lunar eclipse of March 22, 1932]]

=== Lunar Saros 130 ===
* Preceded by: [[April 1903 lunar eclipse|Lunar eclipse of April 12, 1903]]
* Followed by: [[May 1939 lunar eclipse|Lunar eclipse of May 3, 1939]]

=== Inex ===
* Preceded by: [[May 1892 lunar eclipse|Lunar eclipse of May 11, 1892]]
* Followed by: [[April 1950 lunar eclipse|Lunar eclipse of April 2, 1950]]

=== Triad ===
* Preceded by: [[June 1834 lunar eclipse|Lunar eclipse of June 21, 1834]]
* Followed by: [[February 2008 lunar eclipse|Lunar eclipse of February 21, 2008]]

=== Lunar eclipses of 1919–1922 ===
This eclipse is a member of a [[Eclipse cycle#Eclipse cycles|semester series]]. An eclipse in a semester series of lunar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating [[Lunar node|nodes]] of the Moon's orbit.<ref>{{cite web |last1=van Gent |first1=R.H |title=Solar- and Lunar-Eclipse Predictions from Antiquity to the Present |url=http://www.staff.science.uu.nl/~gent0113/eclipse/eclipsecycles.htm#Sar%20%28Half%20Saros%29 |website=A Catalogue of Eclipse Cycles |publisher=Utrecht University |access-date=6 October 2018}}</ref>

The penumbral lunar eclipse on [[March 1922 lunar eclipse|March 13, 1922]] occurs in the next lunar year eclipse set.

{| class="wikitable mw-collapsible mw-collapsed"
!class="nowrap" colspan="9" | [[Lunar eclipse]] series sets from 1919 to 1922
|-
! scope="col" colspan="4" | Ascending node
| rowspan="11" | 
! scope="col" colspan="4" | Descending node
|- style="text-align: center;"
! scope="col" | [[Saros (astronomy)|Saros]]
! scope="col" | Date Viewing
! scope="col" | Type Chart
! scope="col" | [[Gamma (eclipse)|Gamma]]
! scope="col" | Saros
! scope="col" | Date Viewing
! scope="col" | Type Chart
! scope="col" | Gamma
|- style="text-align: center;"
| 110
| [[May 1919 lunar eclipse|1919 May 15]] [[File:Lunar eclipse from moon-1919May15.png|80px]]
| style="text-align:center;" |Penumbral [[File:Lunar eclipse chart close-1919May15.png|80px]]
| −1.0820
| 115
| [[November 1919 lunar eclipse|1919 Nov 07]] [[File:Lunar eclipse from moon-1919Nov07.png|80px]]
| style="text-align:center;" |Partial [[File:Lunar eclipse chart close-1919Nov07.png|80px]]
| 0.9246
|- style="text-align: center;"
| 120
| [[May 1920 lunar eclipse|1920 May 03]] [[File:Lunar eclipse from moon-1920May03.png|80px]]
| style="text-align:center;" |'''Total''' [[File:Lunar eclipse chart close-1920May03.png|80px]]
| −0.3312
| 125
| [[October 1920 lunar eclipse|1920 Oct 27]] [[File:Lunar eclipse from moon-1920Oct27.png|80px]]
| style="text-align:center;" |'''Total''' [[File:Lunar eclipse chart close-1920Oct27.png|80px]]
| 0.2502
|- style="text-align: center;"
| 130
| [[April 1921 lunar eclipse|1921 Apr 22]] [[File:Lunar eclipse from moon-1921Apr22.png|80px]]
| style="text-align:center;" |'''Total''' [[File:Lunar eclipse chart close-1921Apr22.png|80px]]
| 0.4269
| 135
| [[October 1921 lunar eclipse|1921 Oct 16]] [[File:Lunar eclipse from moon-1921Oct16.png|80px]]
| style="text-align:center;" |Partial [[File:Lunar eclipse chart close-1921Oct16.png|80px]]
| −0.4902
|- style="text-align: center;"
| 140
| [[April 1922 lunar eclipse|1922 Apr 11]] [[File:Lunar eclipse from moon-1922Apr11.png|80px]]
| style="text-align:center;" |Penumbral [[File:Lunar eclipse chart close-1922Apr11.png|80px]]
| 1.1228
| 145
| [[October 1922 lunar eclipse|1922 Oct 06]] [[File:Lunar eclipse from moon-1922Oct06.png|80px]]
| style="text-align:center;" |Penumbral [[File:Lunar eclipse chart close-1922Oct06.png|80px]]
| −1.2348
|}

=== Saros 130 ===
{{Lunar Saros series 130}}

=== Tritos series ===
{{Lunar Tritos series August 2008}}

=== Inex series ===
{{Lunar Inex series February 2008}}

=== Half-Saros cycle ===
A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a [[Saros (astronomy)#Relationship between lunar and solar saros .28sar.29|half saros]]).<ref>Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, ''The half-saros''</ref> This lunar eclipse is related to two annular solar eclipses of [[Solar Saros 137]].
{| class=wikitable
![[Solar eclipse of April 17, 1912|April 17, 1912]]
![[Solar eclipse of April 28, 1930|April 28, 1930]]
|-
|[[File:SE1912Apr17H.png|240px]]
|[[File:SE1930Apr28H.png|240px]]
|}

==See also==
*[[List of lunar eclipses]]
*[[List of 20th-century lunar eclipses]]

==Notes==
{{reflist}}

==External links==
*{{LEplot1901 link|1921|Apr|22|T}}

{{Lunar eclipses}}

{{DEFAULTSORT:Lunar eclipse 1921-04}}
[[Category:20th-century lunar eclipses|1921-04]]
[[Category:1921 in science]]

April 1921 lunar eclipse - Revision history

imported>Weatherman4064: /* Related eclipses */