What does Local Hour Angle (LHA) measure relative to the observer's position?

Local Hour Angle (LHA) specifically measures the angle between the observer's meridian—the north-south line that passes through their location—and the meridian of a celestial body. In practical terms, it represents the time that has elapsed since the celestial body last crossed the observer's meridian, expressed in angular measure. LHA is a crucial component in celestial navigation, as it helps determine the position of a celestial body in relation to the observer's location on the Earth.

By calculating LHA, navigators can ascertain where a celestial body is in the sky at a given moment, which is essential for accurately navigating and determining their position. The other options address different aspects of celestial observations but do not pertain directly to the angle measurement of LHA.