The Saros Cycle is used for calculating solar eclipses

The Saros Cycle was invented by the ancient Babylonians more than 5000 years ago and is still used today to accurately calculate solar eclipses. So every 18 years, 11 days, and 8 hours, the sun and moon return to approximately the same relative geometry. This is because we live within God's perfect clock. The sun tells us the time of the day, the moon tells us the time of the month, and the stars tells us the time of the year.