【オンデマンドブック】Nautical Almanac 2027

“The Nautical Almanac” is a high-precision almanac developed for celestial navigation. It provides independently calculated data for practical navigation and observation, including E-values, declinations, meridian passage times, sunrise and sunset, moonrise and moonset, and altitude corrections for the Sun, Moon, planets, and stars.

The numerical values in this publication are generated through an original computational system rather than copied from existing official almanacs. High-precision arithmetic and modern celestial mechanics models are used throughout the calculations.

Rise and set calculations consider local atmospheric conditions such as air temperature and pressure instead of assuming a uniform standard atmosphere. These parameters are based on ERA5 global reanalysis data and interpolated according to latitude, longitude, and seasonal variation to better reflect atmospheric refraction near the horizon.

Relativistic corrections are also included, accounting for gravitational lensing and light-time effects caused by the major planets and 373 asteroids.

Designed with practicality and readability in mind, this work aims to serve navigators, researchers, astronomy enthusiasts, and students of celestial navigation alike.