# May 1966 lunar eclipse

A penumbral lunar eclipse occurred at the Moon’s descending node of orbit on Wednesday, May 4, 1966, with an umbral magnitude of −0.0727. 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 2.75 days after perigee (on May 1, 1966, at 15:20 UTC), the Moon's apparent diameter was larger.

## Visibility

The eclipse was completely visible over Africa, Europe, the western half of Asia, and Antarctica, seen rising over South America and the Atlantic Ocean and setting over east Asia and Australia.

## Eclipse details

Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.
May 4, 1966 Lunar Eclipse Parameters :
| Parameter | Value |
| Penumbral Magnitude | 0.91576 |
| Umbral Magnitude | −0.07272 |
| Gamma | 1.05536 |
| Sun Right Ascension | 02h45m54.8s |
| Sun Declination | +16°01'34.2" |
| Sun Semi-Diameter | 15'51.5" |
| Sun Equatorial Horizontal Parallax | 08.7" |
| Moon Right Ascension | 14h47m34.9s |
| Moon Declination | -15°04'18.1" |
| Moon Semi-Diameter | 16'02.6" |
| Moon Equatorial Horizontal Parallax | 0°58'52.9" |
| ΔT | 36.8 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.
Eclipse season of May 1966 :
| May 4 Descending node (full moon) | May 20 Ascending node (new moon) |
| Penumbral lunar eclipse Lunar Saros 111 | Annular solar eclipse Solar Saros 137 |

## Related eclipses
### Eclipses in 1966

* A penumbral lunar eclipse on May 4.
* An annular solar eclipse on May 20.
* A penumbral lunar eclipse on October 29.
* A total solar eclipse on November 12.

### Metonic

* Preceded by: Lunar eclipse of July 17, 1962
* Followed by: Lunar eclipse of February 21, 1970

### Tzolkinex

* Preceded by: Lunar eclipse of March 24, 1959
* Followed by: Lunar eclipse of June 15, 1973

### Half-Saros

* Preceded by: Solar eclipse of April 30, 1957
* Followed by: Solar eclipse of May 11, 1975

### Tritos

* Preceded by: Lunar eclipse of June 5, 1955
* Followed by: Lunar eclipse of April 4, 1977

### Lunar Saros 111

* Preceded by: Lunar eclipse of April 23, 1948
* Followed by: Lunar eclipse of May 15, 1984

### Inex

* Preceded by: Lunar eclipse of May 25, 1937
* Followed by: Lunar eclipse of April 15, 1995

### Triad

* Preceded by: Lunar eclipse of July 3, 1879
* Followed by: Lunar eclipse of March 4, 2053

### Lunar eclipses of 1966–1969

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.
The penumbral lunar eclipse on August 27, 1969 occurs in the next lunar year eclipse set.
Lunar eclipse series sets from 1966 to 1969 :
| Descending node | Descending node | Descending node | Descending node | Ascending node | Ascending node | Ascending node | Ascending node |
| Saros | Date Viewing | Type Chart | Gamma | Saros | Date Viewing | Type Chart | Gamma |
| 111 | 1966 May 04 | Penumbral | 1.0554 | 116 | 1966 Oct 29 | Penumbral | −1.0600 |
| 121 | 1967 Apr 24 | Total | 0.2972 | 126 | 1967 Oct 18 | Total | −0.3653 |
| 131 | 1968 Apr 13 | Total | −0.4173 | 136 | 1968 Oct 06 | Total | 0.3605 |
| 141 | 1969 Apr 02 | Penumbral | −1.1765 | 146 | 1969 Sep 25 | Penumbral | 1.0656 |

### Metonic series

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 events: May 4 and October 28 |
| Descending node | Ascending node |
| 1966 May 4 - Penumbral (111) 1985 May 4 - Total (121) 2004 May 4 - Total (131) 2023 May 5 - Penumbral (141) | 1966 Oct 29 - Penumbral (116) 1985 Oct 28 - Total (126) 2004 Oct 28 - Total (136) 2023 Oct 28 - Partial (146) 2042 Oct 28 - Penumbral (156) |

### Saros 111

This eclipse is a part of Saros series 111, repeating every 18 years, 11 days, and containing 71 events. The series started with a penumbral lunar eclipse on June 10, 830 AD. It contains partial eclipses from September 14, 992 AD through April 8, 1335; total eclipses from April 19, 1353 through August 4, 1533; and a second set of partial eclipses from August 16, 1551 through April 23, 1948. The series ends at member 71 as a penumbral eclipse on July 19, 2092.
The longest duration of totality was produced by member 35 at 106 minutes, 14 seconds on June 12, 1443. All eclipses in this series occur at the Moon’s descending node of orbit.
| Greatest | First | First | First | First |
| The greatest eclipse of the series occurred on 1443 Jun 12, lasting 106 minutes, 14 seconds. | Penumbral | Partial | Total | Central |
| The greatest eclipse of the series occurred on 1443 Jun 12, lasting 106 minutes, 14 seconds. | 830 Jun 10 | 992 Sep 14 | 1353 Apr 19 | 1389 May 10 |
| Last ||||
| The greatest eclipse of the series occurred on 1443 Jun 12, lasting 106 minutes, 14 seconds. | Central | Total | Partial | Penumbral |
| The greatest eclipse of the series occurred on 1443 Jun 12, lasting 106 minutes, 14 seconds. | 1497 Jul 14 | 1533 Aug 04 | 1948 Apr 23 | 2092 Jul 19 |
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.
Series members 55–71 occur between 1801 and 2092: :
| 55 | 55 | 56 | 56 | 57 | 57 |
| 1804 Jan 26 | 1804 Jan 26 | 1822 Feb 06 | 1822 Feb 06 | 1840 Feb 17 | 1840 Feb 17 |
| 58 | 58 | 59 | 59 | 60 | 60 |
| 1858 Feb 27 | 1858 Feb 27 | 1876 Mar 10 | 1876 Mar 10 | 1894 Mar 21 | 1894 Mar 21 |
| 61 | 61 | 62 | 62 | 63 | 63 |
| 1912 Apr 01 | 1912 Apr 01 | 1930 Apr 13 | 1930 Apr 13 | 1948 Apr 23 | 1948 Apr 23 |
| 64 | 64 | 65 | 65 | 66 | 66 |
| 1966 May 04 | 1966 May 04 | 1984 May 15 | 1984 May 15 | 2002 May 26 | 2002 May 26 |
| 67 | 67 | 68 | 68 | 69 | 69 |
| 2020 Jun 05 | 2020 Jun 05 | 2038 Jun 17 | 2038 Jun 17 | 2056 Jun 27 | 2056 Jun 27 |
| 70 | 70 | 71 | 71 |
| 2074 Jul 08 | 2074 Jul 08 | 2092 Jul 19 | 2092 Jul 19 |

### 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 1835 and 2200 :
| 1835 May 12 (Saros 99) | 1835 May 12 (Saros 99) | 1846 Apr 11 (Saros 100) | 1846 Apr 11 (Saros 100) | | | 1868 Feb 08 (Saros 102) | 1868 Feb 08 (Saros 102) | 1879 Jan 08 (Saros 103) | 1879 Jan 08 (Saros 103) |
| | | | | | | | | 1933 Aug 05 (Saros 108) | 1933 Aug 05 (Saros 108) |
| 1944 Jul 06 (Saros 109) | 1944 Jul 06 (Saros 109) | 1955 Jun 05 (Saros 110) | 1955 Jun 05 (Saros 110) | 1966 May 04 (Saros 111) | 1966 May 04 (Saros 111) | 1977 Apr 04 (Saros 112) | 1977 Apr 04 (Saros 112) | 1988 Mar 03 (Saros 113) | 1988 Mar 03 (Saros 113) |
| 1999 Jan 31 (Saros 114) | 1999 Jan 31 (Saros 114) | 2009 Dec 31 (Saros 115) | 2009 Dec 31 (Saros 115) | 2020 Nov 30 (Saros 116) | 2020 Nov 30 (Saros 116) | 2031 Oct 30 (Saros 117) | 2031 Oct 30 (Saros 117) | 2042 Sep 29 (Saros 118) | 2042 Sep 29 (Saros 118) |
| 2053 Aug 29 (Saros 119) | 2053 Aug 29 (Saros 119) | 2064 Jul 28 (Saros 120) | 2064 Jul 28 (Saros 120) | 2075 Jun 28 (Saros 121) | 2075 Jun 28 (Saros 121) | 2086 May 28 (Saros 122) | 2086 May 28 (Saros 122) | 2097 Apr 26 (Saros 123) | 2097 Apr 26 (Saros 123) |
| 2108 Mar 27 (Saros 124) | 2108 Mar 27 (Saros 124) | 2119 Feb 25 (Saros 125) | 2119 Feb 25 (Saros 125) | 2130 Jan 24 (Saros 126) | 2130 Jan 24 (Saros 126) | 2140 Dec 23 (Saros 127) | 2140 Dec 23 (Saros 127) | 2151 Nov 24 (Saros 128) | 2151 Nov 24 (Saros 128) |
| 2162 Oct 23 (Saros 129) | 2162 Oct 23 (Saros 129) | 2173 Sep 21 (Saros 130) | 2173 Sep 21 (Saros 130) | 2184 Aug 21 (Saros 131) | 2184 Aug 21 (Saros 131) | 2195 Jul 22 (Saros 132) | 2195 Jul 22 (Saros 132) |

### Inex series

This eclipse is a part of the long period inex cycle, repeating at alternating nodes, every 358 synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee). However, groupings of 3 inex cycles (≈ 87 years minus 2 months) comes close (≈ 1,151.02 anomalistic months), so eclipses are similar in these groupings.
Series members between 1801 and 2200 :
| 1821 Aug 13 (Saros 106) | 1821 Aug 13 (Saros 106) | 1850 Jul 24 (Saros 107) | 1850 Jul 24 (Saros 107) | 1879 Jul 03 (Saros 108) | 1879 Jul 03 (Saros 108) |
| 1908 Jun 14 (Saros 109) | 1908 Jun 14 (Saros 109) | 1937 May 25 (Saros 110) | 1937 May 25 (Saros 110) | 1966 May 04 (Saros 111) | 1966 May 04 (Saros 111) |
| 1995 Apr 15 (Saros 112) | 1995 Apr 15 (Saros 112) | 2024 Mar 25 (Saros 113) | 2024 Mar 25 (Saros 113) | 2053 Mar 04 (Saros 114) | 2053 Mar 04 (Saros 114) |
| 2082 Feb 13 (Saros 115) | 2082 Feb 13 (Saros 115) | 2111 Jan 25 (Saros 116) | 2111 Jan 25 (Saros 116) | 2140 Jan 04 (Saros 117) | 2140 Jan 04 (Saros 117) |
| 2168 Dec 14 (Saros 118) | 2168 Dec 14 (Saros 118) | 2197 Nov 24 (Saros 119) | 2197 Nov 24 (Saros 119) |

### Half-Saros cycle

A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros). This lunar eclipse is related to two solar eclipses of Solar Saros 118.
| April 30, 1957 | May 11, 1975 |