blink microscope

blink microscope in astronomy, device for determining a change in position or magnitude (brightness) of a star relative to other stars in the background. Two photographs of the same field or area of the sky are projected so that they precisely coincide. The combined image is viewed through a magnifying eyepiece while light from first one photograph and then the other is interrupted mechanically. A change in position or magnitude of a star can usually be detected since the star will seem to flicker or jump to and fro while the background stars remain steady in both position and brightness.

blink comparator An instrument in which a pair of images can be viewed in rapid succession to detect any differences between them; also known as a blink microscope. The images are usually of the same part of the sky, taken at different times. Any object which has moved or changed brightness will appear to jump or blink as the operator switches between the two images. Blink comparators are used to search for asteroids, variable stars, and novae. Images taken using CCD cameras are compared using software which displays them alternately on a computer monitor.