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Astronomical algorithms and data tables derived from Lunar Tables and Programs from 4000 B.C. to A.D. 8000, by Michelle Chapront-Touzé & Jean Chapront, copyright 1991, and Planetary Programs and Tables from -4000 to +2800, by Pierre Bretagnon & Jean-Louis Simon, copyright 1986, both published by Willmann-Bell, Inc. Used with permission of the copyright holder.

NTP code derived from public domain sources covered by these copyrights.

Geocoding database derived from geonames.org.