Algorithms for Computing Astronomical Phenomena
Skip navigation

The Astronomical Applications Department frequently receives requests for the formulae or algorithms used to compute times of sunrise, sunset, twilight, moonrise, and moonset. Unfortunately, no single formula can be used to predict times of these phenomena accurately over an acceptably wide range of dates and places. The good news, though, is that algorithms to compute times of solar and lunar phenomena have been published in many places and are readily available. A few sources for this information are listed below. The U.S. Navy neither endorses nor recommends any product or vendor.