Meridian Nav vs Navigation Almanac

Meridian is a celestial navigation toolkit built at sea by a working deck officer — fully offline, because mid-ocean is exactly where you need it. SIGHT REDUCTION Compute Hc, Zn and intercept for the Sun, Moon, four planets and 63 navigational stars. Enter your DR position, date/time and sextant altitude — get your line of position. COMPASS ERROR Check gyro error by azimuth of any celestial body — the daily routine, without the almanac and tables. Magnetic variation (WMM2025) is built in for magnetic compass work. STAR FINDER A polar sky-dome view shows exactly which bodies are observable right now from your position — plan your twilight sights before stepping out on the bridge wing. Includes an azimuth-scatter view for picking the best LOP geometry. SUN / MOON Rise, set, meridian passage and twilight times for any position and date. MARINE CHART — FULLY OFFLINE A custom offline vector chart with world time-zone (ZD) boundaries, DST awareness, ports and waypoint routes. Import route files (.rtz / .rou) straight from your ECDIS. CLOCK PLAN Generate the entire voyage's retard/advance schedule from your route — including DST transitions and solar-zone departures. Reorder or edit the changes, then export a clean calendar-style PDF or Excel notice, ready to post on board. UNIT CONVERTER The conversions a navigator actually uses, in two taps. ACCURACY & VALIDATION Every body — Sun, Moon, planets and 63 navigational stars — is cross-checked against JPL ephemeris data (the same source behind the official Nautical Almanac) to arc-minute agreement. Star positions are computed for the current date from the ESA Hipparcos catalogue. Sun azimuth verified at sea against a ship's bridge calculator, and against NOAA's solar calculator (0.000° difference). MADE FOR Deck officers who want a fast backup and sanity check, cadets and officers studying celestial navigation, and anyone who believes a navigator should still be able to find a ship without a satellite. No account. No ads. No subscription. No internet required. One-time purchase. IMPORTANT Meridian is a reference and training aid for celestial navigation. It is not a certified navigation system and does not replace official nautical publications, charts, or type-approved equipment.

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.