USNO Circular 179
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The IAU Resolutions on Astronomical Reference Systems, Time Scales, and Earth Rotation Models: Explanation and Implementation

George H. Kaplan
U.S. Naval Observatory
October 2005


The series of resolutions passed by the International Astronomical Union at its General Assemblies in 1997 and 2000 are the most significant set of international agreements in positional astronomy in several decades and arguably since the Paris conference of 1896. U.S. Naval Observatory Circular 179 explains these resolutions and provides guidance on their implementation. This publication is the successor to USNO Circular 163 (1982), which had a similar purpose for the IAU resolutions passed in 1976, 1979, and 1982. Circular 179 is intended for astronomers, geodesists, engineers, and others with an interest in positional astronomy.

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