subhorizont

Subhorizont is a term used in astronomy and geodesy to describe a specific angular or positional relationship relative to the local horizon. It refers to a point or object that is below the visible horizon but not directly beneath the observer's zenith. More precisely, it indicates a location that is in the observer's lower hemisphere, but not directly overhead. This contrasts with "superhorizont," which would refer to something above the horizon.

In practical terms, subhorizont can be relevant when considering the visibility of celestial objects or terrestrial features. For instance, a star that has set below the apparent horizon is considered subhorizont. Similarly, a geographical location that is on the opposite side of the Earth from the observer, and thus beyond their immediate view, could be described in relation to the subhorizont. The concept is fundamental to understanding celestial navigation, surveying, and the geometry of observation. It helps define the extent of the observable sky and the relationship of an observer to their surrounding environment. The precise angle defining the subhorizont relative to the observer's true horizon can vary depending on the context and the specific astronomical or geodetic model being used.