August 1951 lunar eclipse

August 1951 lunar eclipse
Penumbral eclipse
The Moon's hourly motion shown right to left
DateAugust 17, 1951
Gamma−1.4828
Magnitude−0.8455
Saros cycle108 (71 of 72)
Penumbral93 minutes, 36 seconds
Contacts (UTC)
P12:27:14
Greatest3:14:09
P44:00:50

A penumbral lunar eclipse occurred at the Moon’s ascending node of orbit on Friday, August 17, 1951,[1] with an umbral magnitude of −0.8455. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A penumbral lunar eclipse occurs when part or all of the Moon's near side passes into 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 1.9 days after perigee (on August 15, 1951, at 5:05 UTC), the Moon's apparent diameter was larger.[2]

This eclipse was the third of four penumbral lunar eclipses in 1951, with the others occurring on February 21, March 23, and September 15.

Visibility

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The eclipse was completely visible over eastern and central North America, South America, western Europe, and much of Africa, seen rising over northwestern North America and setting over Eastern Europe, east Africa, and the Middle East.[3]

Simulated views of Earth from moon
Center of moon Lunar north pole

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]

August 17, 1951 Lunar Eclipse Parameters
Parameter Value
Penumbral Magnitude 0.11962
Umbral Magnitude −0.84547
Gamma −1.48284
Sun Right Ascension 09h43m00.9s
Sun Declination +13°43'00.9"
Sun Semi-Diameter 15'47.8"
Sun Equatorial Horizontal Parallax 08.7"
Moon Right Ascension 21h45m34.5s
Moon Declination -15°03'57.5"
Moon Semi-Diameter 16'22.1"
Moon Equatorial Horizontal Parallax 1°00'04.5"
ΔT 29.7 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. The first and last eclipse in this sequence is separated by one synodic month.

Eclipse season of August–September 1951
August 17
Ascending node (full moon)
September 1
Descending node (new moon)
September 15
Ascending node (full moon)
Penumbral lunar eclipse
Lunar Saros 108
Annular solar eclipse
Solar Saros 134
Penumbral lunar eclipse
Lunar Saros 146
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Eclipses in 1951

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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 108

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Inex

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Triad

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Lunar eclipses of 1951–1955

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This eclipse is a member of a semester series. An eclipse in a semester series of lunar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.[5]

The penumbral lunar eclipses on March 23, 1951 and September 15, 1951 occur in the previous lunar year eclipse set, and the lunar eclipses on June 5, 1955 (penumbral) and November 29, 1955 (partial) occur in the next lunar year eclipse set.

Lunar eclipse series sets from 1951 to 1955
Descending node   Ascending node
Saros Date
Viewing
Type
Chart
Gamma Saros Date
Viewing
Type
Chart
Gamma
103 1951 Feb 21
Penumbral
108 1951 Aug 17
Penumbral
−1.4828
113 1952 Feb 11
Partial
0.9416 118 1952 Aug 05
Partial
−0.7384
123 1953 Jan 29
Total
0.2606 128 1953 Jul 26
Total
−0.0071
133 1954 Jan 19
Total
−0.4357 138 1954 Jul 16
Partial
0.7877
143 1955 Jan 08
Penumbral
−1.0907

Metonic series

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This is the third of five Metonic lunar eclipses.

The Metonic cycle repeats nearly exactly every 19 years and represents a Saros cycle plus one lunar year. Because it occurs on the same calendar date, the Earth's shadow will in nearly the same location relative to the background stars.

Metonic lunar eclipse sets 1951–2027
Descending node   Ascending node
Saros Date Type Saros Date Type
103 1951 Feb 21.88 Penumbral 108 1951 Aug 17.13 Penumbral
113 1970 Feb 21.35 Partial 118 1970 Aug 17.14 Partial
123 1989 Feb 20.64 Total 128 1989 Aug 17.13 Total
133 2008 Feb 21.14 Total 138 2008 Aug 16.88 Partial
143 2027 Feb 20.96 Penumbral 148 2027 Aug 17.30 Penumbral

Saros 108

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This eclipse is a part of Saros series 108, repeating every 18 years, 11 days, and containing 72 events. The series started with a penumbral lunar eclipse on July 8, 689 AD. It contains partial eclipses from February 9, 1050 through May 17, 1212; total eclipses from May 28, 1230 through September 23, 1428; and a second set of partial eclipses from October 5, 1446 through June 1, 1825. The series ends at member 72 as a penumbral eclipse on August 27, 1969.

The longest duration of totality was produced by member 35 at 105 minutes, 57 seconds on July 10, 1302. All eclipses in this series occur at the Moon’s ascending node of orbit.[6]

Greatest First
The greatest eclipse of the series occurred on 1302 Jul 10, lasting 105 minutes, 57 seconds.[7] Penumbral Partial Total Central
689 Jul 08
1050 Feb 09
1230 May 28
1266 Jun 19
Last
Central Total Partial Penumbral
1374 Aug 22
1428 Sep 23
1825 Jun 01
1969 Aug 27

Eclipses are tabulated in three columns; every third eclipse in the same column is one exeligmos apart, so they all cast shadows over approximately the same parts of the Earth.

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).[8] This lunar eclipse is related to one partial solar eclipse of Solar Saros 115.

August 12, 1942

See also

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Notes

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  1. ^ "August 16–17, 1951 Penumbral Lunar Eclipse". timeanddate. Retrieved 21 December 2024.
  2. ^ "Moon Distances for London, United Kingdom, England". timeanddate. Retrieved 21 December 2024.
  3. ^ "Penumbral Lunar Eclipse of 1951 Aug 17" (PDF). NASA. Retrieved 21 December 2024.
  4. ^ "Penumbral Lunar Eclipse of 1951 Aug 17". EclipseWise.com. Retrieved 21 December 2024.
  5. ^ van Gent, R.H. "Solar- and Lunar-Eclipse Predictions from Antiquity to the Present". A Catalogue of Eclipse Cycles. Utrecht University. Retrieved 6 October 2018.
  6. ^ "NASA - Catalog of Lunar Eclipses of Saros 108". eclipse.gsfc.nasa.gov.
  7. ^ Listing of Eclipses of series 108
  8. ^ Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros
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