the branch of optics that compensates for image distortions, especially by means of flexible mirrors or membranes.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
noun (functioning as singular)
a technique used to increase the resolution of a ground-based astronomical telescope by counteracting the effects of the atmosphere on the image. A deforming mirror in the light path of the telescope maintains a pointlike image of the celestial body using either a real star or a laser beam as a reference
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012