A group of two stars which appear to constitute a double star due to their being in the same line of sight as seen from the earth, but are actually at different distances.
More example sentences
- At first he figured that such pairs consisted of two stars vastly distant from each other but coincidentally lying along a single line of sight - a visual phenomenon we now call optical doubles.
- The physical doubles (or binary stars) are much more numerous than the optical doubles.
Definition of optical double in:
- The US English dictionary