# June 1991 lunar eclipse

A penumbral lunar eclipse occurred at the Moon’s ascending node of orbit on Thursday, June 27, 1991, with an umbral magnitude of −0.7571. 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 only about 5 hours before apogee (on June 27, 1991, at 8:20 UTC), the Moon's apparent diameter was smaller.
This eclipse was the second of four lunar eclipses in 1991, with the others occurring on January 30 (penumbral), July 26 (penumbral), and December 21 (partial).

## Visibility

The eclipse was completely visible over eastern North America, South America, west and southern Africa, and Antarctica, seen rising over western and northern North America and the eastern Pacific Ocean and setting over Europe, east and north Africa, and the Middle East.

## Eclipse details

Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.
June 27, 1991 Lunar Eclipse Parameters :
| Parameter | Value |
| Penumbral Magnitude | 0.31266 |
| Umbral Magnitude | −0.75714 |
| Gamma | −1.40641 |
| Sun Right Ascension | 06h21m48.4s |
| Sun Declination | +23°20'47.4" |
| Sun Semi-Diameter | 15'44.0" |
| Sun Equatorial Horizontal Parallax | 08.7" |
| Moon Right Ascension | 18h22m33.4s |
| Moon Declination | -24°36'00.3" |
| Moon Semi-Diameter | 14'42.5" |
| Moon Equatorial Horizontal Parallax | 0°53'58.6" |
| ΔT | 57.9 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 June–July 1991 :
| June 27 Ascending node (full moon) | July 11 Descending node (new moon) | July 26 Ascending node (full moon) |
| Penumbral lunar eclipse Lunar Saros 110 | Total solar eclipse Solar Saros 136 | Penumbral lunar eclipse Lunar Saros 148 |

## Related eclipses
### Eclipses in 1991

* An annular solar eclipse on January 15.
* A penumbral lunar eclipse on January 30.
* A penumbral lunar eclipse on June 27.
* A total solar eclipse on July 11.
* A penumbral lunar eclipse on July 26.
* A partial lunar eclipse on December 21.

### Metonic

* Followed by: Lunar eclipse of April 15, 1995

### Tzolkinex

* Preceded by: Lunar eclipse of May 15, 1984
* Followed by: Lunar eclipse of August 8, 1998

### Half-Saros

* Preceded by: Solar eclipse of June 21, 1982
* Followed by: Solar eclipse of July 1, 2000

### Tritos

* Preceded by: Lunar eclipse of July 27, 1980
* Followed by: Lunar eclipse of May 26, 2002

### Lunar Saros 110

* Preceded by: Lunar eclipse of June 15, 1973
* Followed by: Lunar eclipse of July 7, 2009

### Inex

* Preceded by: Lunar eclipse of July 17, 1962
* Followed by: Lunar eclipse of June 5, 2020

### Triad

* Followed by: Lunar eclipse of April 27, 2078

### Lunar eclipses of 1991–1994

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 eclipses on January 30, 1991 and July 26, 1991 occur in the previous lunar year eclipse set.
Lunar eclipse series sets from 1991 to 1994 :
| Ascending node | Ascending node | Ascending node | Ascending node | Descending node | Descending node | Descending node | Descending node |
| Saros | Date Viewing | Type Chart | Gamma | Saros | Date Viewing | Type Chart | Gamma |
| 110 | 1991 Jun 27 | Penumbral | −1.4064 | 115 | 1991 Dec 21 | Partial | 0.9709 |
| 120 | 1992 Jun 15 | Partial | −0.6289 | 125 | 1992 Dec 09 | Total | 0.3144 |
| 130 | 1993 Jun 04 | Total | 0.1638 | 135 | 1993 Nov 29 | Total | −0.3994 |
| 140 | 1994 May 25 | Partial | 0.8933 | 145 | 1994 Nov 18 | Penumbral | −1.1048 |

### 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 be in nearly the same location relative to the background stars.
| Ascending node | Descending node |
| 1991 Jun 27 - penumbral (110) 2010 Jun 26 - partial (120) 2029 Jun 26 - total (130) 2048 Jun 26 - partial (140) 2067 Jun 27 - penumbral (150) | 1991 Dec 21 - partial (115) 2010 Dec 21 - total (125) 2029 Dec 20 - total (135) 2048 Dec 20 - partial (145) |

### Saros 110

This eclipse is a part of Saros series 110, repeating every 18 years, 11 days, and containing 72 events. The series started with a penumbral lunar eclipse on May 28, 747 AD. It contains partial eclipses from August 23, 891 AD through April 18, 1288; total eclipses from April 29, 1306 through September 5, 1522; and a second set of partial eclipses from September 16, 1540 through April 22, 1883. The series ends at member 72 as a penumbral eclipse on July 18, 2027.
The longest duration of totality was produced by member 38 at 103 minutes, 8 seconds on July 3, 1414. All eclipses in this series occur at the Moon’s ascending node of orbit.
| Greatest | First | First | First | First |
| The greatest eclipse of the series occurred on 1414 Jul 03, lasting 103 minutes, 8 seconds. | Penumbral | Partial | Total | Central |
| The greatest eclipse of the series occurred on 1414 Jul 03, lasting 103 minutes, 8 seconds. | 747 May 28 | 891 Aug 23 | 1306 Apr 29 | 1360 May 31 |
| Last ||||
| The greatest eclipse of the series occurred on 1414 Jul 03, lasting 103 minutes, 8 seconds. | Central | Total | Partial | Penumbral |
| The greatest eclipse of the series occurred on 1414 Jul 03, lasting 103 minutes, 8 seconds. | 1468 Aug 04 | 1522 Sep 05 | 1883 Apr 22 | 2027 Jul 18 |
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 60–72 occur between 1801 and 2027: :
| 60 | 60 | 61 | 61 | 62 | 62 |
| 1811 Mar 10 | 1811 Mar 10 | 1829 Mar 20 | 1829 Mar 20 | 1847 Mar 31 | 1847 Mar 31 |
| 63 | 63 | 64 | 64 | 65 | 65 |
| 1865 Apr 11 | 1865 Apr 11 | 1883 Apr 22 | 1883 Apr 22 | 1901 May 03 | 1901 May 03 |
| 66 | 66 | 67 | 67 | 68 | 68 |
| 1919 May 15 | 1919 May 15 | 1937 May 25 | 1937 May 25 | 1955 Jun 05 | 1955 Jun 05 |
| 69 | 69 | 70 | 70 | 71 | 71 |
| 1973 Jun 15 | 1973 Jun 15 | 1991 Jun 27 | 1991 Jun 27 | 2009 Jul 07 | 2009 Jul 07 |
| 72 ||
| 2027 Jul 18 ||

### 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 1904 and 2200 :
| 1904 Mar 02 (Saros 102) | 1904 Mar 02 (Saros 102) | 1915 Jan 31 (Saros 103) | 1915 Jan 31 (Saros 103) | | | | | | |
| | | 1969 Aug 27 (Saros 108) | 1969 Aug 27 (Saros 108) | 1980 Jul 27 (Saros 109) | 1980 Jul 27 (Saros 109) | 1991 Jun 27 (Saros 110) | 1991 Jun 27 (Saros 110) | 2002 May 26 (Saros 111) | 2002 May 26 (Saros 111) |
| 2013 Apr 25 (Saros 112) | 2013 Apr 25 (Saros 112) | 2024 Mar 25 (Saros 113) | 2024 Mar 25 (Saros 113) | 2035 Feb 22 (Saros 114) | 2035 Feb 22 (Saros 114) | 2046 Jan 22 (Saros 115) | 2046 Jan 22 (Saros 115) | 2056 Dec 22 (Saros 116) | 2056 Dec 22 (Saros 116) |
| 2067 Nov 21 (Saros 117) | 2067 Nov 21 (Saros 117) | 2078 Oct 21 (Saros 118) | 2078 Oct 21 (Saros 118) | 2089 Sep 19 (Saros 119) | 2089 Sep 19 (Saros 119) | 2100 Aug 19 (Saros 120) | 2100 Aug 19 (Saros 120) | 2111 Jul 21 (Saros 121) | 2111 Jul 21 (Saros 121) |
| 2122 Jun 20 (Saros 122) | 2122 Jun 20 (Saros 122) | 2133 May 19 (Saros 123) | 2133 May 19 (Saros 123) | 2144 Apr 18 (Saros 124) | 2144 Apr 18 (Saros 124) | 2155 Mar 19 (Saros 125) | 2155 Mar 19 (Saros 125) | 2166 Feb 15 (Saros 126) | 2166 Feb 15 (Saros 126) |
| 2177 Jan 14 (Saros 127) | 2177 Jan 14 (Saros 127) | 2187 Dec 15 (Saros 128) | 2187 Dec 15 (Saros 128) | 2198 Nov 13 (Saros 129) | 2198 Nov 13 (Saros 129) |

### 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 1846 and 2200 :
| 1846 Oct 04 (Saros 105) | 1846 Oct 04 (Saros 105) | 1875 Sep 15 (Saros 106) | 1875 Sep 15 (Saros 106) | | |
| 1933 Aug 05 (Saros 108) | 1933 Aug 05 (Saros 108) | 1962 Jul 17 (Saros 109) | 1962 Jul 17 (Saros 109) | 1991 Jun 27 (Saros 110) | 1991 Jun 27 (Saros 110) |
| 2020 Jun 05 (Saros 111) | 2020 Jun 05 (Saros 111) | 2049 May 17 (Saros 112) | 2049 May 17 (Saros 112) | 2078 Apr 27 (Saros 113) | 2078 Apr 27 (Saros 113) |
| 2107 Apr 07 (Saros 114) | 2107 Apr 07 (Saros 114) | 2136 Mar 18 (Saros 115) | 2136 Mar 18 (Saros 115) | 2165 Feb 26 (Saros 116) | 2165 Feb 26 (Saros 116) |
| 2194 Feb 05 (Saros 117) ||

### 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 partial solar eclipses of Solar Saros 117.
| June 21, 1982 | July 1, 2000 |