1911 Encyclopædia Britannica/Almacantar

ALMACANTAR (from the Arabic for a sun-dial), an astronomical term for a small circle of the sphere parallel to the horizon; when two stars are in the same almacantar they have the same altitude. The term was also given (1880) to an instrument invented by S. C. Chandler to determine the latitude or correct the timepiece, of great value because of its freedom from instrumental errors.