What is indicated by the Circle of Equal Altitude in celestial navigation?

The Circle of Equal Altitude in celestial navigation represents a crucial concept in determining a ship's position at sea. It indicates all points on the Earth's surface where an observer would experience the same altitude for a celestial body, such as the sun or stars, at a specific time.

When navigators use this circle, they are able to derive their position relative to the geographic position of the celestial body being observed. By plotting their observations and calculating their distance to the geographic position, they can refine their navigation and establish their exact location on the Earth's surface. This is because the circle effectively encompasses a region where the observed angle from the ship to the celestial body is constant, which directly correlates to the distance from the geographic position.

The other options do not accurately describe what the Circle of Equal Altitude represents, as it does not specify the angle of the celestial body, the altitude of the ship itself, or the position of the star independent of the observer's location. Instead, it focuses on the relationship between the observer's position and the geographic position of the celestial body based on the altitude measurements taken.