Celestial Navigation 360 vs Navigation Almanac

Each measurement taken with a sextant (a 'sight') converts to a line of position (LoP) on a chart, the intersections of two or more such lines providing a position fix Use this app to plan/enter sights and inspect the resulting LoPs -- Features -- * Realtime or frozen computed horizon in panoramic projection. Use for star/planet identification, sight preparation and entry, true bearings etc. * Sight reduction (ephemerides calculated internally) for the 58 almanac-listed navigational stars. Extendable to the sun, moon and planets via subscription * Almanac rising/setting/transits/twilights * Sextant-like functionality via the camera Licensed under Apple's standard End User License Agreement (EULA), available at: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Navigation Almanac is a complete celestial-navigation toolkit for iPhone and iPad. It reduces a sight, tabulates the almanac data you would otherwise look up on paper, and works entirely offline - no signal, no subscription, no account. SIGHT REDUCTION Enter your position and the date and time in UTC or local time, then pick a body. You get azimuth and computed altitude, GHA, LHA, SHA and declination, semi-diameter and horizontal parallax, along with the magnetic variation from the WMM-2025 model and the current value of ΔT. ALMANAC The Sun, Moon, Venus, Mars, Jupiter and Saturn together with the 57 navigational stars, each with azimuth, altitude, hour angles and declination for the moment you have chosen. RISE, SET AND TWILIGHT Rise, meridian transit and set for any body, with civil and nautical twilight at the Sun's standard altitudes (-0°50′ / -6° / -12°), shown in UTC or local time. SKY VIEW The sky drawn as a chart of azimuth against altitude, or as a full-sky dome with the zenith at the centre. Background stars, constellation lines, and a predicted GNSS satellite layer computed from a bundled orbital catalogue. GPS Live position, course and speed over ground, altitude and horizontal accuracy, the magnetic variation at your position, and the ephemeris of the selected body. One tap fills the observer position for a reduction. COMPASS ERROR Solve gyro and magnetic compass error from an observed bearing, with variation and deviation kept separate, the way the correction is actually applied on the bridge. FIX CALCULATOR Cross two lines of position from your reductions, advance the first line for the vessel's run between sights, and read off the observed position. WORKS OFFLINE The ephemerides are computed on the device from the VSOP87 and ELP2000 series with IAU 1980 nutation - they are not downloaded. Everything above works with the phone in airplane mode, weeks from shore. SIXTEEN LANGUAGES English, Russian, Ukrainian, French, Spanish, Italian, Portuguese, German, Dutch, Polish, Swedish, Danish, Greek, Turkish, Latvian and Simplified Chinese. The navigation terminology in each was taken from that country's own nautical almanac and navigation textbooks rather than translated word for word. NAVIGATIONAL WARNINGS Warnings in force from the national coordinators of the worldwide navigational warning service, grouped by country and by NAVAREA, with the full text of every message and the positions read out of it. The feed is rebuilt every hour and the last copy stays on the device, so it is there when the signal is not. This is an experimental feature and the screen says so: the data is gathered automatically, it can lag behind the broadcast, and it can be incomplete. It does not relieve you of the requirement to receive Maritime Safety Information over NAVTEX and SafetyNET as provided for by SOLAS. Navigation Almanac is a computational aid. Carry the official almanac and tables required for your voyage.