An Etymological Dictionary of Astronomy and Astrophysics

A device that allows two images of the sky taken at different times to be optically superimposed so that changes in star brightness or moving objects can be detected.

Etymology (EN): → stereo-; comparator, from L. comparare
“to place together, match,” from compar “alike, matching,” → com-; → partial

• -tor.

Etymology (PE): Ham-sanj-gar “comapartor,” from ham-, → com-,

• sanj stem of sanjidan “to compare” + -gar,
  → -or; → stereo-.