Definition
Volume 1 tabulates altitude and true azimuth directly for seven selected stars per LHA of Aries, requiring no declination entry and giving a fix with minimal work, but it needs replacing every five years or so as precession accumulates. Volumes 2 and 3 cover bodies with declinations up to 29 degrees and are perpetual. Precision is one minute of arc rather than the tenth achievable with NP401, which is ample for ocean passage-making.
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