Solar Almanac – GHA and Declination for Sextant Navigation (2026–2040), calculated with high precision using the JPL DE440s ephemerides.
This Solar Almanac – GHA and Declination for Sextant Navigation (2026–2040) is an invaluable resource for navigators seeking reliable data for future voyages.
Coordinates of the Sun’s apparent center — true equinox of date
UT hours (UTC from the ship’s clock)
The difference between UTC and UT1 remains less than 1 second and is negligible for astronomical navigation.
The accuracy of the ephemerides remains stable over the entire period covered.
1 No progressive drift.
2 No discontinuity at year changes.
3 No cumulative calculation error.
Symbols used:
GHA (Greenwich Hour Angle of the Sun)
Dec (Declination of the Sun)
d (Change in declination per hour)
pp (Increment of GHA for minutes and seconds)
UT (Universal Time (UTC))
The goal is to set sail with only a minimal number of pages, while retaining all the information needed for celestial navigation, without relying on any external source.
1) Annual ephemerides
(20 pages) giving the Sun’s GHA and declination for the year.
Combined with the « EasySextant » Sun Reduction Tables folder, these tables form a complete celestial navigation kit for calculating a line of position. No additional documents or calculator are required—just a sextant, a watch, and the Sun Reduction Tables folder.
You can also include the folder containing the eight fully worked examples. They are an excellent way to refresh your sextant navigation skills after a long period without practice.
Astronomical Data Source
The solar positions (GHA and Declination) used in this almanac are computed from the JPL DE440s planetary ephemeris, developed by the Jet Propulsion Laboratory (NASA).
Released in 2020, DE440s provides high-precision positions of the Sun, Moon, and planets based on decades of observational data (spacecraft tracking, radar ranging, and lunar laser measurements).
Its use ensures that the solar data for 2026–2040 are derived from a modern scientific standard consistent with professional astronomical references.