It contains astronomical data to help in the navigation of the ship. It is published by the hydrographic office of various government or semi-governmental agency. In India, it is Published in Dehra Dun.
Information in NA
Altitude correction table to convert sextant altitude to true altitude.
Then there is a calendar of the year with information on eclipses that will occur during that year and location on the earth where they are visible.
Content on the daily page of Nautical Almanac.
Each page contains information of three consecutive days.
- GHA and Declination of the sun and the moon for every hour of GMT.
- Gives information to calculate the time of sunrise, sunset and meridian passage of the sun.
- It also provides information to calculate the time of moonrise, Moonset, and passage of the moon.
- GHA Aries for every hour of GMT.
- GHA and Declination of 4 planets that are helpful in navigation. (Venus, Mars,Jupiter, Saturn).
- SHA and Declination of 57 stars once for all 3 days.