When using the Altitude-Intercept Method, what two values do we compare?

In the Altitude-Intercept Method, navigators compare the calculated height and the observed height. The calculated height is derived from the celestial body's position based on time and a specific location, usually found using nautical almanacs and sight reduction tables. The observed height is obtained through direct observation of the celestial body using a sextant.

By comparing these two values, navigators can determine their position on the Earth. If the observed height is greater than the calculated height, it suggests that the observer is located closer to the celestial body than anticipated, while a lower observed height indicates a farther distance. This method is critical for ensuring accurate navigation, as it allows sailors to correct their course and improve their situational awareness on the open sea.