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October 1939 lunar eclipse

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October 1939 lunar eclipse
Partial eclipse
The Moon's hourly motion shown right to left
DateOctober 28, 1939
Gamma−0.4581
Magnitude0.9876
Saros cycle135 (19 of 71)
Partiality203 minutes, 22 seconds
Penumbral346 minutes, 5 seconds
Contacts (UTC)
P13:43:14
U14:54:40
Greatest6:36:19
U48:18:01
P49:29:19

A partial lunar eclipse occurred at the Moon’s descending node of orbit on Saturday, October 28, 1939,[1] with an umbral magnitude of 0.9876. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A partial lunar eclipse occurs when one part of the Moon is in the Earth's umbra, while the other part is in the Earth's penumbra. 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. Occurring about 5.3 days after apogee (on October 23, 1939, at 0:05 UTC), the Moon's apparent diameter was smaller.[2]

This lunar eclipse was the last of an almost tetrad, with the others being on May 14, 1938 (total); November 7, 1938 (total); and May 3, 1939 (total).

This was the last partial lunar eclipse of the first set of partial eclipses in Lunar Saros 135 as well as the largest partial lunar eclipse of the 20th century.

Visibility

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The eclipse was completely visible over North America and western South America, seen rising over northeast Asia and eastern Australia and setting over eastern South America, west and central Africa, and Europe.[3]

Eclipse details

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Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.[4]

October 28, 1939 Lunar Eclipse Parameters
Parameter Value
Penumbral Magnitude 2.04769
Umbral Magnitude 0.98764
Gamma −0.45812
Sun Right Ascension 14h06m46.1s
Sun Declination -12°50'04.8"
Sun Semi-Diameter 16'05.9"
Sun Equatorial Horizontal Parallax 08.9"
Moon Right Ascension 02h07m11.5s
Moon Declination +12°25'18.8"
Moon Semi-Diameter 15'11.2"
Moon Equatorial Horizontal Parallax 0°55'44.2"
ΔT 24.4 s

Eclipse season

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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 October 1939
October 12
Ascending node (new moon)
October 28
Descending node (full moon)
Total solar eclipse
Solar Saros 123
Partial lunar eclipse
Lunar Saros 135
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Eclipses in 1939

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Metonic

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Tzolkinex

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Half-Saros

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Tritos

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Lunar Saros 135

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Inex

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Triad

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Lunar eclipses of 1937–1940

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Lunar eclipse series sets from 1937–1940
Ascending node   Descending node
Saros Date
viewing
Type
chart
Saros Date
viewing
Type
chart
110 1937 May 25
Penumbral
115 1937 Nov 18
Partial
120 1938 May 14
Total
125 1938 Nov 07
Total
130 1939 May 03
Total
135 1939 Oct 28
Partial
140 1940 Apr 22
Penumbral
145 1940 Oct 16
Penumbral

Saros 135

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It was part of Saros series 135.

Half-Saros cycle

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A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).[5] This lunar eclipse is related to two total solar eclipses of Solar Saros 142.

October 21, 1930 November 1, 1948

See also

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Notes

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  1. ^ "October 27–28, 1939 Partial Lunar Eclipse". timeanddate. Retrieved 18 December 2024.
  2. ^ "Moon Distances for London, United Kingdom, England". timeanddate. Retrieved 18 December 2024.
  3. ^ "Partial Lunar Eclipse of 1939 Oct 28" (PDF). NASA. Retrieved 18 December 2024.
  4. ^ "Partial Lunar Eclipse of 1939 Oct 28". EclipseWise.com. Retrieved 18 December 2024.
  5. ^ Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros
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