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Ephemeris Computation Office, NAOJ

The Ephemeris Computation Office (ECO) estimates various astronomical phenomena including the apparent places of the Sun/Moon/planets on the basis of international standards and publishes the "Calendar and Ephemeris" as part of the compilation of almanacs, which is one of NAOJ's raisons d'ĂȘtre. ECO announces its summary as "Reki Yoko" in the first official gazette issued in February. Since the information on koyomi or citizen's calendar is closely related to human life, ECO also compiles Ephemeris section of "Rika Nenpyo" (Chronological Scientific Tables) to make them available for many people.


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