ezAlmanac Celestial Navigation

ezAlmanac Celestial Navigation

Example Nautical Almanac Daily Page with Highlighting
Zoom and Pan on Page with Highlighted Data
Page to Enter Observation and View Nautical Almanac Altitude Corrections
View Plot of Observations Against Expected Value.  View Nautical Almanac Values to Determine GP of Observed Object
Sight Reduction View Showing Plotted LOPs and Pub 229 Values for Sight Reduction
Star Map View Showing Internally Calculated Hc and Az Values for Each Object
Screen displaying sight reduction plotting on a map.  Zoom out to see GP of each object with full "circle of position".  Zoom in to see normal sight reduction plot on the map.
Screen showing compass check result for a bearing observation
Screen showing data for altitude observation in a sight reduction form

App details

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Navigation & maps

About ezAlmanac Celestial Navigation

Celestial navigation has never been easier! With ezAlmanac and a sextant you will be finding your fix like a pro in no time!

ezAlmanac will help you perform celestial navigation exactly as it has been done for hundreds of years. It produces all Nautical Almanac (1961-2059) 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 ezAlmanac do all of the work. Simply enter the basic sight parameters, make and enter your observations, and ezAlmanac 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, ezAlmanac 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. ezAlmanac 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 ezAlmanac 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 ezAlmanac 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.

ezAlmanac performs all astronomical calculations using the NOVAS 3.1 software from the US Naval Observatory (USNO) and a JPL ephemeris that covers the years 1961 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, ezAlmanac is fully functional with no dependency on the internet.

ezAlmanac has been a favorite for iPad users for more than 10 years and it is now available for Windows 10!

Key features

  • Generate and print Nautical Almanac pages (1961-2059) and all related correction tables
  • Animated star map allows easy identification of all navigational bodies and show their movement on a selected day
  • Calculates a predicted altitude that can be used to preset your sextant to before making an observation
  • Full sight reduction of all observations showing all steps and where each value comes from
  • Generate and print reports of your fixes including summary data, plotted LOPS and fully filled in sight reduction forms
  • Performs compass checks for up to 5 devices using a single bearing observation of a navigational body
  • Generate and print compass check reports for ships records