What is the primary function of the Nautical Almanac?

The primary function of the Nautical Almanac is to provide essential data for celestial navigation calculations. This almanac includes information on the positions of celestial bodies, such as the sun, moon, planets, and stars, at various times throughout the year. Navigators use this data to calculate their exact position at sea by sighting these celestial bodies using sextants or similar tools. The information is vital for determining latitude and longitude, especially when GPS is not available or in cases where traditional navigation methods are preferred or necessary.

The other choices do not align with the primary purpose of the Nautical Almanac. While a Nautical Almanac can support navigation, it does not directly guide ship handling procedures, provide communication protocols, or assess port conditions. Each of those functions is typically pursued through separate resources and tools specialized for those specific tasks.