The American Practical Navigator (Bowditch)

The American Practical Navigator, commonly called Bowditch after its original author Nathaniel Bowditch, is a navigation reference now maintained and issued by the U.S. National Geospatial-Intelligence Agency, an official government body responsible for navigational and geospatial standards. Its authority comes from official maintenance and continuous revision to remain accurate for real navigational use, not from any single author's ongoing involvement, since Bowditch himself died in 1838 and the work has been updated by the agency ever since. The atlas cites it for factual, technical content such as celestial navigation and calendar mechanics rather than for any religious claim. Its limit here is exactly that it is a navigation manual, not a source on the religious or symbolic meaning some traditions attach to celestial navigation.