iNA Digitial Nautical Almanac

iNA computes all ephemeris data available in the daily pages of the USNO Nautical Almanac. This information is required when doing astronomical computations for celestial navigation, local noon, sunrise, and others. The program computes GHA, Dec, SHA, SD, HP, magnitudes, sunrise, sunset, LAN, twilight times, moonrise, moonset, moon age and phase for sun, moon, 5 planets, and 173 stars; all at GMT which is longitude 0. INA also computes addition useful information not included in the Nautical Almanac such as ephemeris for Mercury, Hc at LAN, bearing of sunrise and sunset (amplitudes), and the GHA of Aries midway between civil and nautical twilights for star planning.

INA's internal celestial almanac is valid for the years 1582 through 2800 AD.

iNA requires no external resources to complete its computations. Internet access is not required to use this program or to access any of its help files.

iNA returns results at GMT which is longitude 0. Interpolation for your specific location and/or times other than on the hour, must be computed manually. We recommend using StarPilot which has a built-in Nautical Almanac and will perform all the complex calculations for you.