''Resolving power'' is the ability of an imaging device to separate (i.e.that is, to see as distinct) points of an object that are located at a small [[angular separation|angular distance]] or it is the power of an optical instrument to separate far away objects, that are close together, into individual images. The term ''[[Optical resolution|resolution]]'' or ''minimum resolvable distance'' is the minimum distance between distinguishable objects in an image, although the term is loosely used by many users of microscopes and telescopes to describe resolving power. As explained below, diffraction-limited resolution is defined by the Rayleigh criterion as the angular separation of two point sources when the maximum of each source lies in the first minimum of the diffraction pattern ([[Airy disk]]) of the other. In scientific analysis, in general, the term "resolution" is used to describe the [[Accuracy and precision|precision]] with which any instrument measures and records (in an image or spectrum) any variable in the specimen or sample under study.
