The Fifth Orbit Catalog

Brian Mason

US Naval Observatory

The USNO has recently completed a successor to the "Fourth Catalog of Orbits of Visual Binary Stars", published in 1983 by Charles Worley & Wulff Heintz. The web-based "Fifth Catalog" contains the latest orbital elements for over 1,200 binaries, together with links to ephmerides, extensive notes, and detailed figures. A description of the catalog, its applicability to field calibration its statistics, and its general characteristics, will be discussed.

A major effort in creation of the catalog has involved development of an objective method for grading the quality of each orbit. The criteria used in grading both the orbits and the observations which went into them will be described.