Tetrad (astronomy)


In astronomy, a tetrad is a set of four total lunar eclipses within two consecutive years.[1]
The frequency of tetrads varies by century with the frequency of total lunar eclipses. This repeating cycle is called a tetradia. See Eclipse cycle for more information.
List of tetrad events
1949–2000
| Saros | Date Viewing |
Type Chart |
Saros | Date Viewing |
Type Chart | |
|---|---|---|---|---|---|---|
| 1949–50 | ||||||
| Descending node | Ascending node | |||||
| 121 | 1949 Apr 13
|
Total
|
126 | 1949 Oct 07
|
Total
| |
| 131 | 1950 Apr 02
|
Total
|
136 | 1950 Sep 26
|
Total
| |
| 1967–68 | ||||||
| Descending node | Ascending node | |||||
| 121 | 1967 Apr 24
|
Total
|
126 | 1967 Oct 18
|
Total
| |
| 131 | 1968 Apr 13
|
Total
|
136 | 1968 Oct 6
|
Total
| |
| 1985–86 | ||||||
| Descending node | Ascending node | |||||
| 121 | 1985 May 04
|
Total
|
126 | 1985 Oct 28
|
Total
| |
| 131 | 1986 Apr 24
|
Total
|
136 | 1986 Oct 17
|
Total
| |
2001–51
| Saros | Date Viewing |
Type Chart |
Saros | Date Viewing |
Type Chart | |
|---|---|---|---|---|---|---|
| 2003–04 | ||||||
| Descending node | Ascending node | |||||
121
|
2003 May 16
|
total
|
126
|
2003 Nov 09
|
total
| |
131
|
2004 May 04
|
total
|
136
|
2004 Oct 28
|
total
| |
| 2014–15 | ||||||
| Ascending node | Descending node | |||||
122
|
2014 Apr 15
|
Total
|
127 |
2014 Oct 08
|
Total
| |
132
|
2015 Apr 04
|
Total
|
137
|
2015 Sep 28
|
Total
| |
| 2032–33 | ||||||
| Ascending node | Descending node | |||||
| 122 | 2032 Apr 25
|
Total
|
127 | 2032 Oct 18
|
Total
| |
| 132 | 2033 Apr 14
|
Total
|
137 | 2033 Oct 08
|
Total
| |
| 2043–44 | ||||||
| Descending node | Ascending node | |||||
| 123 | 2043 Mar 25
|
Total
|
128 | 2043 Sep 19
|
Total
| |
| 133 | 2044 Mar 13
|
Total
|
138 | 2044 Sep 07
|
Total
| |
| 2050–51 | ||||||
| Ascending node | Descending node | |||||
| 122 | 2050 May 06
|
Total
|
127 | 2050 Oct 30
|
Total
| |
| 132 | 2051 Apr 26
|
Total
|
137 | 2051 Oct 19
|
Total
| |
See also
- Total penumbral lunar eclipse § Summary frequency of total penumbral, total umbral and tetrad events 501–2500 for statistics by century
- Blood moon prophecy Apocalyptic preaching of John Hagee and Mark Biltz in part based on the observed phenomenon.








































































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