#horizontal coordinates
- Almucantar — A small circle on the celestial sphere parallel to the horizon, passing through all points that share the same angular altitude above it; an imaginary line used in positional astronomy and classic celestial navigation to measure and compare the vertical coordinates of celestial bodies.
- altazimuth — An astronomical instrument or mechanical mount utilized for determining the position of celestial bodies or for guiding telescopes and cameras, structurally characterized by rotation around two perpendicular axes: a horizontal axis (for measuring altitude or height above the horizon) and a vertical axis (for measuring azimuth).