What is defined as the angular distance above the horizon?

• A. Declination
• B. Hour Angle
• C. Altitude
• D. Azimuth

Answer: (C)

The term that describes the angular distance above the horizon is altitude. In celestial navigation, altitude refers to the angle between the observer's local horizontal plane and the line of sight to an object in the sky, such as a star or the sun. It is measured in degrees and helps navigators determine how high an object is in the sky, which is crucial for accurate positioning and navigation.

In contrast, declination refers to the angular distance of an object north or south of the celestial equator, hour angle relates to the time since the object has crossed the observer's meridian, and azimuth is the angle from a reference direction, typically north, to the vertical line from the observer to the object. Each of these terms serves a distinct purpose in navigation, but they do not describe the angle above the horizon as altitude does.