semidiameter correction

semidiameter correction

[¦sem·i·dī′am·əd·ər kə′rek·shən]
(navigation)
The sextant altitude correction that, when applied to the observation of the upper or lower limb of a celestial body, determines the altitude of the center of that body.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.