A penumbral lunar eclipse occurred at the Moon’s descending node of orbit on Tuesday, August 26, 1980,[1] with an umbral magnitude of −0.2531. 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 1.7 days before perigee (on August 27, 1980, at 20:05 UTC), the Moon's apparent diameter was larger.[2]

Visibility

The eclipse was completely visible over central and eastern North America, South America, and west Africa, seen rising over western North America and the central Pacific Ocean and setting over central and eastern Africa, Europe, and the Middle East.[3]

Eclipse details

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

August 26, 1980 Lunar Eclipse Parameters
Parameter Value
Penumbral Magnitude 0.70891
Umbral Magnitude −0.25310
Gamma −1.16082
Sun Right Ascension 10h19m57.4s
Sun Declination +10°23'14.8"
Sun Semi-Diameter 15'49.7"
Sun Equatorial Horizontal Parallax 08.7"
Moon Right Ascension 22h21m14.5s
Moon Declination -11°30'44.4"
Moon Semi-Diameter 16'27.2"
Moon Equatorial Horizontal Parallax 1°00'23.3"
ΔT 51.1 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.

Eclipse season of July–August 1980
July 27
Descending node (full moon)
August 10
Ascending node (new moon)
August 26
Descending node (full moon)
Penumbral lunar eclipse
Lunar Saros 109
Annular solar eclipse
Solar Saros 135
Penumbral lunar eclipse
Lunar Saros 147

Eclipses in 1980

Metonic

Tzolkinex

Half-Saros

Tritos

Lunar Saros 147

Inex

Triad

Lunar eclipses of 1977–1980

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 eclipse on July 27, 1980 occurs in the next lunar year eclipse set.

Lunar eclipse series sets from 1977 to 1980
Ascending node   Descending node
Saros Date
Viewing
Type
Chart
Gamma Saros Date
Viewing
Type
Chart
Gamma
112 1977 Apr 04
Partial
−0.9148 117 1977 Sep 27
Penumbral
1.0768
122 1978 Mar 24
Total
−0.2140 127 1978 Sep 16
Total
0.2951
132 1979 Mar 13
Partial
0.5254 137 1979 Sep 06
Total
−0.4305
142 1980 Mar 01
Penumbral
1.2270 147 1980 Aug 26
Penumbral
−1.1608

Saros 147

This eclipse is a part of Saros series 147, repeating every 18 years, 11 days, and containing 70 events. The series started with a penumbral lunar eclipse on July 2, 1890. It contains partial eclipses from September 28, 2034 through May 27, 2431; total eclipses from June 6, 2449 through October 5, 2647; and a second set of partial eclipses from October 16, 2665 through May 1, 2990. The series ends at member 70 as a penumbral eclipse on July 28, 3145.

The longest duration of totality will be produced by member 37 at 105 minutes, 18 seconds on August 1, 2539. All eclipses in this series occur at the Moon’s descending node of orbit.[6]

Greatest First
The greatest eclipse of the series will occur on 2539 Aug 01, lasting 105 minutes, 18 seconds.[7] Penumbral Partial Total Central
1890 Jul 02
2034 Sep 28
2449 Jun 06
2485 Jun 28
Last
Central Total Partial Penumbral
2593 Sep 02
2647 Oct 05
2990 May 01
3134 Jul 28

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.

Tritos series

This eclipse is a part of a tritos cycle, repeating at alternating nodes every 135 synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee), but groupings of 3 tritos cycles (≈ 33 years minus 3 months) come close (≈ 434.044 anomalistic months), so eclipses are similar in these groupings.

Series members between 1801 and 2078
1806 Jan 05
(Saros 131)
1816 Dec 04
(Saros 132)
1827 Nov 03
(Saros 133)
1838 Oct 03
(Saros 134)
1849 Sep 02
(Saros 135)
1860 Aug 01
(Saros 136)
1871 Jul 02
(Saros 137)
1882 Jun 01
(Saros 138)
1893 Apr 30
(Saros 139)
1904 Mar 31
(Saros 140)
1915 Mar 01
(Saros 141)
1926 Jan 28
(Saros 142)
1936 Dec 28
(Saros 143)
1947 Nov 28
(Saros 144)
1958 Oct 27
(Saros 145)
1969 Sep 25
(Saros 146)
1980 Aug 26
(Saros 147)
1991 Jul 26
(Saros 148)
2002 Jun 24
(Saros 149)
2013 May 25
(Saros 150)
2078 Nov 19
(Saros 156)

Half-Saros cycle

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 two partial solar eclipses of Solar Saros 154.

August 20, 1971 August 31, 1989

See also

Notes

  1. ^ "August 25–26, 1980 Penumbral Lunar Eclipse". timeanddate. Retrieved 4 January 2025.
  2. ^ "Moon Distances for London, United Kingdom, England". timeanddate. Retrieved 4 January 2025.
  3. ^ "Penumbral Lunar Eclipse of 1980 Aug 26" (PDF). NASA. Retrieved 4 January 2025.
  4. ^ "Penumbral Lunar Eclipse of 1980 Aug 26". EclipseWise.com. Retrieved 4 January 2025.
  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 147". eclipse.gsfc.nasa.gov.
  7. ^ Listing of Eclipses of series 147
  8. ^ Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros


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