Leap Day Solar and Lunar Eclipses
By Alex Vincent
Not many eclipses occur on Leap Year Day (bissextile day) February 29. Only 26 take place on this date between the years –2000 and +3000. February 29 would not have existed before 46 BC and so the dates given are from the Julian calendar. The Julian calendar is used up to 1582 and then the Gregorian calendar thereafter. The BC years are given astronomically e.g –1436 is the same as 1437 BC. The AD years are given as + up to 1000 AD e.g +956 is 956 AD. Astronomically the year 0 is used, but not historically.
Some of these eclipses take place on 28/29 February and some February 29/March 1. When mid eclipse is on February 28 or March 1 the start or end of the eclipse can occur on bissextile day or it is bissextile day in some part of the world where the eclipse is taking place. For this reason our next bissextile day eclipse will be an annular solar eclipse on February 28 2044. Here the very beginning of the partial phase will occur on February 29. The solar eclipse of February 28 2864 is total in Britain, but no part of it occurs in the eastern hemisphere where it is already February 29. These ones are omitted.
The Moon’s phases take place on or near the same date every 19 years. This cycle is known as the Metonic cycle, which was discovered by Meton in the 5th century BC. For this reason eclipses can occur on these dates every 19 years. For example there was a total solar eclipse on July 22 2009 and will be repeated again with another on July 22 2028. This will only occur for four to five consecutive eclipses every 19 years then 19 years later it will be full or new Moon and the eclipse will occur one month earlier.
In the case of eclipses occurring on Leap Day, this can only take place in 76 years. The only case with solar eclipses in the 5000 year period given here were in +108 and +184 and both were partials. In the case of lunar eclipses the only case is –664 and –588, which are both penumbrals. There are a few lunar eclipses in this 5000 year period where there is a period of 84 years.
Eclipses occur in cycles known as a Saros of 18 years ten or eleven days depending on the number of leap years. For example the total solar eclipse of July 11 2010 will be repeated one Saros later on July 22 2028. Eclipses are governed by a Saros series, which last between 1226 to 1515 years for solar and 1262 to 1550 years for lunar. There are between 69 and 85 solar eclipses per solar Saros series and between 70 and 87 for lunar Saros series. For example solar Saros series number 136 will last 1262 years.
Solar eclipses
Between the years –2000 and +3000 there are eleven solar eclipses, which take place on the bissextile day February 29 in some part of the world. Two of these are total, four are annular and five are partial. For both solar and lunar eclipses, if the magnitude is less than 1.000 it is partial and greater than 1.000 it is total.
Below is a table of these eclipses.
Date of eclipse   Type of eclipse   Magnitude  Saros No.
-1436 Feb 29            Partial            0.9059            7
-896 Feb 29               Total             1.0652            35
-356 Feb 29               Total             1.0628            63
+108 Feb 29            Partial             0.0082           51
+184 Feb 29            Partial            0.6947            91
+648 Feb 29            Annular          0.9257            79
1188 Feb 29            Annular          0.9294            107
1756 Feb 29 **         Annular          0.9787            126
2044 Feb 29 *          Annular          0.9600            121
2416 Feb 29            Partial            0.1275            127
2872 Feb 29            Partial            0.3864            144
* Mid eclipse occurs on February 28. ** Mid eclipse occurs on March 1
The first of these is the eclipse in –1436, which was a partial only event with a magnitude of 0.9059. As can be seen from the above table, the last total solar eclipse to take place on February 29 was in –356 and there will not be another until after the year +3000.
Lunar eclipses
Between the years –2000 and +3000 there are 17 lunar eclipses, which take place on the bissextile day February 29 in some part of the world. Some of these are total.
Below is a table of these eclipses.
Date of eclipse   Type of eclipse   Magnitude  Saros No.
-1668 Feb 29**            Umbral            1.637            6
-1584 Feb 29**            Umbral             1.0609         17
-1128 Feb 29               Umbral             0.587            34
-1044 Feb 29**            Penumbral       0.660           45
-664 Feb 29                 Penumbral       0.405            22
-588 Feb 29                 Penumbral      0.163            62
-208 Feb 29*               Penumbral      0.908            39
-124 Feb 29                Umbral            0.816            50
+332 Feb 29*             Umbral             1.275            67
+416 Feb 29*             Umbral            1.454            78
+956 Feb 29*             Umbral            0.081            106
+964 Feb 29**            Penumbral      0.749            77
1420 Feb 29              Umbral             0.167            94
1504 Feb 29**           Umbral             1.101            105
1896 Feb 29*            Umbral             0.872            131
2268 Feb 29              Umbral            1.665            137
2640 Feb 29              Umbral            1.254            143
* Mid eclipse occurs on February 28. ** Mid eclipse occurs on March 1
After 2640 there will not be another lunar eclipse on February 29 until 3012, which will be a partial umbral. There is also a 372 year period where lunar phases and eclipses occur on or near the same date. For example all the Leap Day lunar eclipses in 1896, 2268, 2640 and 3012 are 372 years apart. Like the Metonic cycle, this only applies to several consecutive eclipses then 372 years later it will be a full or new Moon. The eclipse will take place one month later.
There are more lunar eclipses, which take place on Leap Day in this 5000 year period than that of solar eclipses. The reason for this greater frequency is that lunar eclipses are visible from a much wider area than those of solar eclipses.
Some Saros series, which have occurred or will take place on Leap Day, are in existence today. For solar eclipses they are Saros No.s 121, 126, 127 and 144. For lunar eclipses they are Saros No.s 131, 137, 143 and 149. The author has seen and photographed those of solar Saros No. 126 and lunar Saros No.s 131, 137 and 149. Below are two examples.
EQ MountEQ MountEQ MountEQ Mount
         Solar eclipse. 01.08.08. Saros 126         Total lunar eclipse. 28.09.15. Saros 137
The total solar eclipse (partial in the UK) of August 1 2008 (Saros 126) produced an annular on March 1 1756, but only the end of the partial phase occurred on February 29. The total lunar eclipse on September 28 2015 (Saros 137) will produce a total on February 29 2268, which will be our next Leap Day lunar eclipse.
Images copyright Alex Vincent