# Meridian Nav — Meridian > Offline marine navigation aid with GPS, charts, route management, and celestial calculations. (iPhone/iPad app by SEUNGHYEOK CHOI.) - Source: https://appshunter.io/ios/app/meridian-nav/id6774504786 (this page in markdown: same URL + `.md`) - Developer: [SEUNGHYEOK CHOI](https://appshunter.io/developer/6774504788) - Category: Navigation, Reference - Price: $0.99 - Age rating: 4+ - Requires: iOS 13.0 · 36 MB - Languages: American English - Released: 2026-06-02 - Data updated: 2026-08-26 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/meridian-nav/id6774504786/reviews.md ## What is Meridian Nav? 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. ## Key features - Offline GPS position monitoring - Offline chart and waypoint display - .rtz route import and management - Navigation calculations - Celestial body data - Sun/moon event times ## Recent user reviews (1 of 1) All indexed reviews: https://appshunter.io/ios/app/meridian-nav/id6774504786/reviews.md ### 5/5 — Excellent App for Sailors *2026-06-04* Excellent app for marine navigation! The offline functionality is incredibly useful and reliable. I especially appreciate the accurate GPS positioning, route management, waypoint calculations, and celestial navigation features. The interface is clean and easy to use, making it a valuable tool for sailors and navigation enthusiasts. It’s impressive that so many features work without an internet connection. Highly recommended for anyone interested in marine navigation! ## Frequently asked questions about Meridian Nav ### What is Meridian Nav? Meridian Nav is a fully offline marine navigation aid designed for sailors and navigators. It offers features like GPS position monitoring, offline chart display, route management, and various navigational calculations. ### Can Meridian Nav be used without an internet connection? Yes, all functions of Meridian Nav can be used without an internet connection, making it ideal for offshore use. ### What types of calculations does Meridian Nav offer? Meridian Nav provides GPS-based position, speed, course, and altitude display, as well as calculations for distance/time to waypoints, target speed based on ETA, and celestial body positions. ### Does Meridian Nav support route planning? Yes, Meridian Nav allows you to import, store, and restore .rtz routes, and it can calculate the distance and time to the next and target waypoints based on your current position. ### Is Meridian Nav suitable for primary navigation? Meridian Nav is a navigation aid and calculation tool, not certified for primary or sole navigation. It should always be used in conjunction with official charts, nautical almanacs, approved navigation equipment, and professional judgment. ### What devices does Meridian Nav support? Meridian Nav is currently supported on iPhone devices. ### How much does Meridian Nav cost? Meridian Nav is available for a one-time purchase price of $0.99. ### When was Meridian Nav last updated? Meridian Nav was last updated on June 25, 2026, with version 1.2.0. ## Version history (last 5 releases) ### 1.3.0 — 2026-07-14 • Amplitude compass check — verify gyro/compass error against the rising or setting Sun. Event time and declination are computed automatically. • New Latitude panel (Noon / Polaris) — latitude by the noon Sun with a live meridian-passage predictor, or by Polaris at twilight. No tables needed. • Celestial fix plot — reduced sights now draw on a plotting sheet: lines of position, the least-squares fix and its scatter, at a glance. • Moon phase — the Sun / Moon screen now shows an illustrated phase disc with the illuminated fraction and the Moon's age. • Higher-resolution offline chart — coastlines sharpen automatically as you zoom in. • Clock Plan improvements — zone-change scheduling is now DST-aware and aligns each change to the ship's actual local zone. • Built-in glossary — every calculator's help now explains the terms and abbreviations it uses (Zn, Ho, intercept, amplitude, and more). • Celestial engine validated against JPL ephemeris data — Sun, Moon, planets and 63 navigation stars agree to arc-minute accuracy. ### 1.2.1 — 2026-07-05 • Celestial engine precision upgrade — every body (Sun, Moon, planets, 63 stars) now cross-checked against JPL ephemeris data to arc-minute agreement • Star positions now computed from the Hipparcos catalogue for the current date (fixes several star positions) • Light / Dark / System theme with a main-menu toggle • Clock Plan: calendar-style PDF & Excel export for on-board notices • Map: cleaner control menu, theme-aware chart colors • Various UI fixes across devices ### 1.2.0 — 2026-06-25 • 항법 계산기: 시각대(ZD) 처리 정확도 개선 — 어떤 시간대에서도 방위·고도·시계산이 정확하게 계산됩니다. • 전후진 계획표(Clock Plan): 현재 GPS 위치에서 목적지까지의 거리(DTG)를 기준으로 계획을 생성합니다. 해도에 띄운 항로를 따라 계산하며, 항로가 없거나 맞지 않으면 안내해 줍니다. • 해도: 시간대(ZD) 경계선 표시 개선. • 전반적인 안정성 및 정확도 향상. • Nav Calculator: improved time-zone (ZD) handling — azimuth, altitude and sight reduction now compute correctly in every zone. • Clock Plan: builds the advance/retard schedule from your current GPS position and the distance-to-go, following the route on the Marine Chart, with a warning when no matching route is loaded. • Marine Chart: clearer time-zone (ZD) boundary rendering. • General stability and accuracy improvements. ### 1.1.2 — 2026-06-09 UI 개선 및 사용성 향상 • 메인 메뉴 레이아웃 개선 — 스크롤 없이 한 화면에 표시 • 지도 검색창 및 홈 버튼 위치 수정 (상단 상태바 영역 겹침 해결) • 숫자 키보드 닫기 버튼 추가 • 일출 / 자오선 통과 / 일몰 아이콘 개선 • 앱 아이콘 업데이트 • 기타 UI 안정성 개선 UI Improvements & Usability Enhancements • Main menu redesigned to fit on one screen without scrolling • Fixed search bar and home button overlapping the status bar on map screen • Added keyboard dismiss button for numeric input fields • Improved sunrise / meridian transit / sunset icons • Updated app icon • General UI improvements ### 1.1.1 — 2026-06-06 루트 파일 지원 확장 / 천체 계산 정확도 및 항법 추천 기능 개선 * 달·행성 위치 계산 정확도 향상 * Star Finder: Best Body 추천에 달 위상 반영, 초승달 제외, 달 우선순위 하향 * Compass Error: 고도 기반 경고 메시지 추가 (수평선 아래, 저고도, 고고도) * NOW 버튼이 폰 표시 시간 기준 Zone Description 오프셋 반영 * 일부 UI 레이블 명칭 변경 * Compass Error 계산에 WMM2025 기반 Variation 자동 입력 기능 추가 * Route File 불러오기 지원 확장 (.rtz, .txt, .csv, .rou) * Route 파일 불러오기 안정성 및 오류 처리 개선 * 항법 계산 및 WPT 관련 내부 로직 안정화 Expanded route file import support / Improved celestial calculation accuracy and navigation recommendations. * Enhanced moon & planet position accuracy * Star Finder: Best Body now factors in moon phase; crescent moons excluded; Moon deprioritized per real-world practice * Compass Error: altitude-based warnings added (below horizon, low altitude, high altitude) * NOW button reflects phone's local time with Zone Description offset * Minor UI label updates * Added automatic WMM2025-based magnetic variation input for Compass Error * Expanded route file import support (rtz, .txt, .csv, .rou) * Improved route import stability and error handling * Refined internal navigation and waypoint calculation logic --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-26.*