Eclipse
Eclipse ->> FREQUENCY OF ECLIPSES If the earth’s orbit, or the ecliptic , were in the same plane as the moon’s orbit, two total eclipses would occur during each lunar month, a lunar eclipse at the time of each full moon, and a solar eclipse at the time of each new moon. The two orbits, however, are inclined, and, as a result, eclipses occur only when the moon or the sun is within a few degrees of the two points, called the nodes, where the orbits intersect. Periodically both the sun and the moon return to the same position relative to one of the nodes, with the result that eclipses recur at regular intervals. The time of the interval, called the saros, is a little more than 6585.3 days or about 18 years, 9 to 11 days, depending on the number of intervening leap years, and 8 hours. The saros, known since the time of ancient Babylonia, corresponds almost exactly to 19 returns of the sun to the same node, 242 returns of the moon to the same node, and 223 lunar months. The disparity ...