swinging the arc

swinging the arc

[′swiŋ·iŋthə ′ärk]
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The process of rotating a sextant about the line of sight to the horizon to determine the foot of the vertical circle through a body being observed. Also known as rocking the sextant.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.