To determine latitude at local noon, what is combined with the Sun's altitude?

To determine latitude at local noon, the Sun's altitude is combined with the Sun's declination on that day. During local noon, the Sun reaches its highest point in the sky for that day at a specific latitude.

The latitude can be calculated using the angle of the Sun above the horizon (the altitude) and the Sun's declination, which is the angle between the rays of the Sun and the plane of the Earth's equator. The declination changes throughout the year as the Earth orbits the Sun, meaning it varies with the date. By knowing both the altitude of the Sun at local noon and the declination for that specific date, one can use trigonometric formulas to solve for latitude.

The other options, while related to navigation, do not directly contribute to determining latitude in this specific context. Local time does not provide the necessary astrophysical data to calculate latitude, the ship's current position does not inform about the Sun's position relative to Earth, and the azimuth of stars is not relevant to calculating the latitude based on the Sun's position at noon.