EZ Celestial Navigation

Celestial navigation has never been easier!

Whether you're an experienced navigator, a student, or an instructor, ezAlmanacOne provides the tools to navigate by the sun, moon, planets, and stars.

With ezAlmanacOne and a sextant, take observations, reduce sights, plot lines of position, and determine your fix. Every calculation is shown, making the app both a powerful navigation tool and an exceptional learning resource.

THREE METHODS OF SIGHT REDUCTION

Choose from three complete sight reduction methods:

Pub. 229 Sight Reduction Tables

NAO Concise Sight Reduction Tables

Law of Cosines

Switch methods at any time and compare the resulting lines of position on the plot. NAO sight reduction reports include the actual table values in the traditional Nautical Almanac sight reduction form.

COMPLETE NAUTICAL ALMANAC AND SIGHT REDUCTION TABLES

ezAlmanacOne generates Nautical Almanac pages for 1960 through 2059, plus Pub. 229 and NAO sight reduction tables. All appear in their familiar printed format, with zooming, panning, and highlighting to locate values. Access tables for manual navigation or save and print them for use aboard your vessel.

AUTOMATED NAVIGATION — EVERY STEP SHOWN

Enter your sight information and sextant observations. ezAlmanacOne:

Corrects sextant observations to obtain observed altitude.

Determines the celestial body's geographic position.

Performs sight reduction using your selected method.

Calculates and plots lines of position (LOPs).

Determines your fix from intersecting LOPs.

Every step is displayed so you can understand and verify the results.

LEARN CELESTIAL NAVIGATION AS YOU USE IT

Values obtained from the Nautical Almanac or sight reduction tables are marked with a book icon. Tap it to open the actual table page with the correct row, column, and value highlighted. This direct connection between calculations and traditional tables is especially valuable for students and instructors.

COMPASS CHECKS AND BEARING OBSERVATIONS

Use celestial bearing observations to determine compass errors and check up to five compasses or bearing devices from one observation. Save or print detailed compass check reports for your vessel's records.

PDF REPORTS AND DOCUMENTATION

Create high-resolution Nautical Almanac pages, sight reduction reports, and compass check reports. View, save, or print them with the integrated PDF viewer. Printable sight reduction forms and plotting sheets support manual navigation. A Quick Start Guide, usage examples, and detailed documentation help you get started.

ACCURATE CALCULATIONS — NO INTERNET REQUIRED

Astronomical calculations use NOVAS software from the U.S. Naval Observatory and a JPL planetary ephemeris covering 1960 through 2059. Magnetic declination uses NOAA's World Magnetic Model. All calculations run on your device, with no internet connection required — even offshore.

DESIGNED FOR MODERN DEVICES

Built using .NET MAUI, ezAlmanacOne supports all Android devices with flexible layouts, multiple orientations, and zooming and panning.

Whether navigating offshore, practicing, or teaching, ezAlmanacOne combines modern convenience with traditional celestial navigation.

Recent changes:
Now with three Sight Reduction Methods: Choose between Pub. 229 tables, NAO Concise Sight Reduction Tables, and the Law of Cosines. Switch methods at any time and compare the resulting plotted lines of position.

New NAO Tables: Full support for the Nautical Almanac's concise sight reduction tables, including interactive highlighting and detailed table values in sight reduction reports.