1. A circle on the celestial sphere parallel to the horizon, passing through a point at a constant altitude above the horizon.
Usage: astronomy; also spelled almucantarat

Examples

• The almucantar helps astronomers locate stars at specific altitudes above the horizon.
• Navigation charts often include almucantars to aid in celestial position-finding.
• An observer at the equator will see almucantars as perfect circles in the sky.
• The almucantar system is useful for measuring the angular height of celestial objects.