noun
- a circle on the celestial sphere parallel to the horizon, connecting all points of equal altitude above the horizon
Usage: astronomy; navigation
Examples
- The navigator used almacantars to determine the ship's latitude by measuring star altitudes.
- In celestial navigation, almacantars are essential for plotting positions on a star chart.
- The almacantar passing through the zenith is the horizon itself.
- Astronomers trace almacantars to track the apparent motion of celestial bodies.