| 释义 |
air almanac Air Almanac[′er ′ȯl·mə‚nak] (navigation) A periodical publication of astronomical data useful to and designed primarily for air navigation. A joint publication of the U.S. Naval Observatory and the Royal Greenwich Observatory, listing the Greenwich hour angle and declination of various celestial bodies at 10-minute intervals, the time of sunrise, sunset, moonrise, and moonset, and other astronomical information arranged in a form convenient for navigators; each publication covers 4 months. air almanacA joint publication of the National Almanac Office and the U.S. Naval Observatory and Her Majesty's Nautical Almanac Office (UK). It covers a four-month period and contains tabulated values of the Greenwich hour angles and the declination of the selected celestial bodies, along with additional celestial data used in navigation. |