The Nautical Almanac - Sun and stars

astronomical data for mariners - year 2017

" The Nautical Almanac of the stars " (PDF or excel spreadsheet) The excel version generates the essential data needed for the pratice of celestial navigation - This free software  creates daily pages (a printable sheet - A4). All these astronomical data and information allow mariners to calculate the ships position with the traditional method of the celestial navigation (using a sextant).

The new "PDF" version for year 2017 contains Increments and correction tables for Sun and Aries, corrections to apply to the observed altitude of Sun and fixed star, conversion of arc to time, speed-time-distance table.

description of  the nautical almanac ( astronomical almanac for mariners )- "excel" version

By entering latitude and longitude of the estimated position excel automatically calculates the times of the astronomical events in U.T. (Greenwich Mean Time) : twilight, sunrise and sunset.

view of the The Nautical Almanac of the stars

The excel spreadsheet (software) shows :

Sun  :  Greenwich hour angle (G.H.A.) and  declination tabulated at hourly intervals including increments, semi-diameter  and meridian passage at Greenwich :

Nautical Almanac - the sun - g.h.a. and declination

sun - variation of g.h.a. and declination

 Aries  :  hour tables ( Greenwich hour angle - sideral time ) :

G.H.A. of aries in the nautical almanac

 Stars  :  position tables ( sideral hour angle - S.H.A. and declination ) - 64 stars are tabulated (Polaris included) :

S.H.A. and Declination of the stars in the nautical almanac

On the nautical almanac the astronomical events are shown according to the geographic coordinates : nautical twilights, sunrise and sunset . Times are expressed in Universal Time (U.T.)  - Latitude 50° 24,5'  North and longitude 0°00,1 West are the geographic coordinates (approx.) of the lightvessel "Greenwich" at the southern entrance to The Channel ( in the middle of the separation zone ).  New coordinates are required for the real estimated position (or country, town etc.). :

sunset, sunrise, twilight and semidiameter of the sun in the nautical almanac

In the sheet " standard latitudes "  events at fixed latitudes/Greenwich longitude are shown like a traditional nautical almanac  :

twilight and sunrise in the nautical almanac


Hour angles and declinations are calculated with a precision equal to that given in the traditional Nautical Almanac. VSOP87 Theory has been  incorporated in the program and allows the calculation of the position of the sun with an error not exceeding 2". Results has been rounded to the nearest value (0,1 arcminute).

disclaimer and use

This is a freeware software  (excel spreadsheet) but the redistribution is forbidden and the download is possible from this website only. This Almanac does not intend to substitute the traditional Nautical Almanac. The software has the following characteristic: " as is " without any express or implied warranties of any kind. The user assumes full responsibility for the use of the software.

nautical almanac - download area

DOWNLOAD " The Nautical Almanac of the stars - 2017" 
DOWNLOAD - Increments and corrections tables for HA and declination
Altitude correction tables
Starfinder for mariners

In October the version of the next year will be issued. The file is available in "binary format " ( office 2007 ) too : make a request at This email address is being protected from spambots. You need JavaScript enabled to view it.

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