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.








































































_(cropped).jpg)
