Question 1621Navigation General

The correct answer is B) zenith distance. The radius of a circle of equal altitude for a body equals the body's zenith distance. The zenith distance is the angular distance between the body and the observer's zenith, or the point directly overhead. This relationship is defined in the principles of celestial navigation, which is a key part of the US Coast Guard Captain's License Examinations. The other options are incorrect because: A) declination is the angular distance of a celestial body north or south of the celestial equator, C) altitude is the angular distance of a body above the horizon, and D) polar distance is the angular distance of a body from the celestial pole.