Nautical Calculator Preview vs EZ Celestial Navigation
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Nautical Calculator Preview
This app provides comprehensive tools for marine navigation, including real-time ship movement, route planning, and advanced sailing calculations. It also offers features for collision avoidance, maneuvering, and learning maritime regulations and signaling.
- Real-time ship movement
- Route planning
- Mercator and Great Circle sailing
- Collision avoidance
- Maneuvering calculations
- COLREGs and maritime signaling
- Offline GPS
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The application to assist in solving the most important marine problems. - For Marine Navigation +Real-Time Ship Movement; +Route Plan; + Mercator Sailing. + Greate Circle Sailing. + Meridional parts. + Plane Sailing. + Traverse Sailing. + Wheel over. + Current and wind sailing. + Allowing for current and wind. + Calculate true wind and apparent wind on a ship running. + Nautical Almanac + Two Lop Fix + Three Lop Fix + Correcting marine sextant altitude of sun and stars. + Probability Distribution Function. + Standard Deviation and Error. + Offline GPS. - For Maneuvering : -Avoid collisions -Change of station in cases: + with time specified + with speed specified + with course specified + Course and speed of another ship. + Closest point of approach(CPA). + Ability to reach another ship going faster. + Close or open to another ship in cases : - as quickly as possible. - on a constant bearing. - with time specified. + Maneuver to intercept a target ship going faster. + Maneuver to intercept ahead a target ship. + Close to another ship as close as possible. +Keep watch for a target ship within a range of distances; +Maneuvering with added calculating of turning. +Bearing and distance to another ship in advance. - For Learning : +International regulations for preventing collisions at sea (COLREG) include Rules; Lights signs; Shapes signs and Sounds signs. + Marine signalizations include Flag signaling; Morse signaling by hand; Morse code. + Maritime buoyage system. + Unit Conversion for Maritime. + Glossary of Marine Navigation. +Maritime Theory. +Global Lighthouses System. author Vu Cong The. vucongthe@gmail.com - Các tính toán hàng hải và vận động tàu, bao gồm : +Dịch chuyển của tàu theo thời gian thật; +Lập kế hoạch hành trình; +Hành trình theo hải đồ Mercator +Hành trình theo cung vòng lớn. +Vĩ độ tiến +Dự tính vị trí tàu một hướng và nhiều hướng. +Tính và đè độ dạt gió dòng. +Tính toán lượn vòng của tàu. +Tính toán gió thực và gió biểu kiến trên tàu đang hành trình. +Lịch thiên văn hàng hải. +Phương pháp hai đường vị trí. +Hiệu chỉnh độ cao mặt trời và sao đo bằng sextant hàng hải. +Tính hàm phân phối xác suất. +Tính sai số chuẩn và độ lệch chuẩn. +Hướng đi, vận tốc của tàu mục tiêu. +Tránh va. +Các thông số ở điểm tiếp cận CPA. +Các thông số trận địa với thời gian hoặc khoảng cách cho trước. + Xác định khả năng tiếp cận tàu mục tiêu có vận tốc lớn hơn. +Thay đổi khoảng cách tới một tàu khác với : - Thời gian ngắn nhất. - Thời gian cho trước. - Phương vị không đổi. +Vận động cắt mũi hoặc lái một tàu mục tiêu có vận tốc lớn hơn. +Vận động cắt mũi một tàu mục tiêu. +Tiếp cận một tàu khác ở cự ly ngắn nhất. +Tính các yếu tố trận địa với thời gian hoặc cự ly cho trước. +Thay đổi trận địa trong các trường hợp: -với thời gian cho trước. -với vận tốc cho trước. -với hướng đi cho trước. +Vận động trong dải khoảng cách. +Tính toán lượn vòng trong vận động. -Tra cứu hàng hải bao gồm : + Qui tắc tránh va quốc tế (COLREG) : Nội dung các điều luật, Tín hiệu đèn, Dấu hiệu, Tín hiệu âm thanh +Thông hiệu hàng hải : Thông tin cờ hiệu, thông tin cờ tay, mã morse +Hệ thống phao tiêu hàng hải +Thuật ngữ Tiếng Anh Hàng hải. +Chuyển đổi đơn vị trong hàng hải. +Lý thuyết hàng hải. +Hệ thống hải đăng toàn cầu. Các giao diện hiển thị hai ngôn ngữ : Tiếng Anh và tiếng Việt Tác giả : Vũ Công Thế. vucongthe@gmail.com
EZ Celestial Navigation
This app simplifies celestial navigation using a sextant, providing tools to calculate your position at sea. It offers automated calculations or manual table access, with features for observation archiving and compass checks. Ideal for learning and practicing traditional navigation methods.
- Automated sight reduction and LOP plotting
- Manual Nautical Almanac and Pub. 229 table access
- Observation archiving and restoration
- Compass check functionality
- Printable Nautical Almanac pages and reports
- Universal app for iOS and macOS
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Celestial navigation has never been easier! With ezAlmanacOne and a sextant you will be finding your fix like a pro in no time! ezAlmanacOne is an evolution of the iPad version of ezAlmanac with the modern user interface used in the Windows 10 version of ezAlmanac. All of the features of ezAlmanac plus new features including: - Universal app runs on iPad, iPhone, iPod touch, and the new MacBook with M1 processor. - Supports all device orientations. All screens support zoom and pan. - Make bearing observations to perform compass checks. - Archive saved observations and restore observation data from an archive. - Includes quick start guide, usage examples, and other documentation to learn celestial navigation. - Print/Output Nautical Almanac pages, observation reports, and other app documentation. ezAlmanacOne will help you perform celestial navigation exactly as it has been done for hundreds of years. It produces all Nautical Almanac (1960-2059) and Pub. 229 tables exactly as you are used to seeing them in the printed form. All tables can be accessed directly for manual usage if you choose to do so. Since they are produced by the software they support zooming and panning, and you can highlight in the tables to easily find the correct value to use. Most users, however, will prefer to let ezAlmanacOne do all of the work. Simply enter the basic sight parameters, make and enter your observations, and ezAlmanacOne will do the rest. It performs all of the steps to correct your observation, find GP of the object, do the sight reduction, and plot the LOP. No steps are skipped and all details are shown. Click where the LOPs cross in the plot and you have found your fix! Besides finding your fix, ezAlmanacOne is one of the best tools available to perform compass checks from a bearing observation of one of the navigational bodies. The compass check function supports checking up to 5 devices from a single bearing observation. ezAlmanacOne will also create a report of your compass check that can be saved as a PDF file or printed for the ships records. Celestial navigation instructors love ezAlmanacOne because it does celestial navigation exactly as they teach it. Values obtained from the Nautical Almanac and Pub. 229 are clearly identified with an icon of the book. When you press the book icon you are taken to the page that has that value with the row, column and value highlighted. Even when ezAlmanacOne is doing all the work, it can teach you how to do it manually using the books. For manual celestial navigation you can generate and print Nautical Almanac pages to use as a backup on a passage. You can even print the sight reduction forms and plotting sheets you will need. ezAlmanacOne performs all astronomical calculations using the NOVAS 3.1 software from the US Naval Observatory (USNO) and a JPL ephemeris that covers the years 1960 through 2059. It also implements WMM-2020, the latest World Magnetic Model software available from NOAA, to compute magnetic declination. Since all calculations are performed in the software, ezAlmanacOne is fully functional with no dependency on the internet.
Screenshots
Verdict
The clearest difference is price: Nautical Calculator Preview at Free against EZ Celestial Navigation's $29.99. EZ Celestial Navigation's advantage is ads (none vs shown) and ratings volume (26 vs 1). On rating, update cadence, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Nautical Calculator Preview is free to download; EZ Celestial Navigation costs $29.99 up front. Neither carries in-app purchases, so what you see is what you pay.
On the App Store both sit at effectively the same score — 5.0 for Nautical Calculator Preview against 4.9 for EZ Celestial Navigation. That said, the two scores are not equally well evidenced: EZ Celestial Navigation has 26 ratings behind it against 1, so its average is the more settled of the two.
Nautical Calculator Preview ships an update every 3 weeks, EZ Celestial Navigation monthly. The most recent releases landed on August 7, 2026 and September 16, 2026 respectively.
| Parameter | Nautical Calculator Preview | EZ Celestial Navigation |
|---|---|---|
| Price | Free — better | $29.99 |
| Rating | 5.0 (1 ratings) — better | 4.9 (26 ratings) |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | 1 | 26 — better |
| Update frequency | Every 3 weeks — better | Monthly |
| Ads | Yes | No — better |
| In-app purchases | No | No |
| Monetization | Ad-supported — better | Paid |
| Best chart rank | — | #19 — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 13.0 | 13.0 |
| Further details — not scored | ||
| Size | 36 MB | 153 MB |
| Age rating | 4+ | 4+ |
| Developer | The Vu Cong | EZ Celestial LLC |
Customer experience
Nautical Calculator Preview
EZ Celestial Navigation
In-app purchases
Nautical Calculator Preview
No in-app purchases
EZ Celestial Navigation
No in-app purchases
Questions
Is Nautical Calculator Preview free?
Is EZ Celestial Navigation free?
Which has better reviews, Nautical Calculator Preview or EZ Celestial Navigation?
Do Nautical Calculator Preview or EZ Celestial Navigation have ads?
Which is updated more often, Nautical Calculator Preview or EZ Celestial Navigation?
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