Sight reduction tables for air navigation - United States

These tables are recommended by HM Nautical Almanac Office for the reduction of astronomical sights at sea. Although the tables were designed originally for air navigation they are ideally suited for use at sea using altitude observation of stars taken with a marine sextant. No matter where you are the tables provide pre-computed altitude and azimuth of seven selected stars for obtaining position lines and making astronomical sight reductions.;The best stars for making a three-star fix have been individually marked. The tables contain true azimuth to the nearest degree and calculated altitude to the nearest minute of arc. The latitude range is in whole degrees from 89 degrees north to 89 degrees south. The tables are entered with argument Local Hour of Aries in steps of l degree from O degrees to 360 degrees except at very high latitudes. The tables are valid for the decade 1990 to 2000, and with the auxiliary tables and explanation they provide a self-contained method of sight reduction.