Saros History

The total eclipse of 1997 March 9 is the sixtieth member of saros series 120 (Table 13), as defined by van den Bergh [1955]. All eclipses in the series occur at the Moon's descending node and gamma_1 increases with each member in the series. The family is at a mature stage having begun with a partial eclipse at high southern hemisphere latitudes (near the pole) on 933 May 27. During the first century, seven partial eclipses occurred with the eclipse magnitude of each succeeding event gradually increasing. Finally, the first umbral eclipse occurred on 1059 August 11. The event was a six minute annular eclipse and had a remarkable 765 kilometer wide path which passed through Antarctica and the Indian Ocean. During the next four centuries, the series continued to produce annular eclipses whose maximum durations gradually decreased as each path shifted further and further north. The eclipse path of 1510 May 8 included both annular and total segments as the nature of the series began to metamorphose. The events of 1528 May 18 and 1546 May 29 were also annular/total eclipses with ever increasing total durations. The first completely total eclipse of the series occurred on 1564 June 8 over open ocean in the Pacific.

The path of each succeeding eclipse continued to shift north as the umbral duration gradually exceeded two minutes. This trend ended after the total eclipse of 1672 August 22. This was due primarily to Earth's passage through the Autumnal Equinox which tilted northern latitudes above Earth's geocenter faster than the progression of eclipse paths in the saros series. By 1870 December 22, the eclipse paths were once again shifting northward. This particular eclipse is of historical interest in that it passed through southern Spain where a number of scientific expeditions were sent to make observations of the event. The French astronomer Pierre Jules Janssen escaped the German siege of Paris in a balloon in order to travel to Algiers for the eclipse. Unfortunately, his observations were thwarted by clouds. U. S. astronomer Charles A. Young was more successful in Spain where his observations revealed that the chromosphere is responsible for producing both the flash spectrum and dark line spectrum observed in the Sun's photosphere.

Three saros cycles later, the famous New York City eclipse occurred on 1925 January 24. Since it was known that the southern limit of this total eclipse passed somewhere through Manhattan, it was possible to pin down the exact limit to between 95th and 97th Streets by stationing observers at every intersection between 72nd and 135th Streets. The total eclipse of 1961 February 15 was widely viewed through southern Europe. The most recent member of saros 120 occurred in the Pacific Northwest on 1979 February 26. The path of totality passed through parts of Washington, Oregon, Montana and Manitoba. After 1997, there are only two more total eclipses in the series (Figure 6). The eclipse of 2015 March 20 occurs in the North Atlantic where its broad track passes between Great Britain and Iceland. The path includes Svalbard Island before literally ending at the North Pole. Finally, the last central eclipse of saros 120 takes place on 2033 March 30. This 778 kilometer wide path begins in eastern most Siberia and covers the Bering Strait and the northern half of Alaska. From Nome, the two and a half minute total phase will occur with the Sun just 7deg. above the horizon. The remaining nine eclipses are all visible from high northern latitudes, each event with a progressively smaller magnitude. The series ends with the partial eclipse of 2195 July 7. A detailed list of eclipses in saros series 120 appears in Table 13.

In summary, Saros series 120 includes 71 eclipses with the following distribution:

Saros 120     Partial   Annular   Ann/Tota  Total     
Non-Central      16     0         0         0         
Central          --     25        3         27        

Next section

Table of Contents