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.

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
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See also

References
  1. Total Penumbral lunar eclipses, Jean Meeus, 1980
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