Methods and optics of perceiving color in a black-and-white grating are described. A sample grating which produces the effect is included. (JN)

A retroreflector is a mirror that removes distortion from a light beam. Describes experiments using the retroreflector as well as related phenomena. (JN)

Presents a nonmathematical approach to help students understand that there are two types of coherence and to associate coherence as a property of the illumination at an object itself. The approach also lends itself to an introduction to the Fourier approach for analyzing imaging systems. (JN)

Discusses a laboratory exercise simulating the paths of light rays through spherical water drops by applying principles of ray optics and geometry. Describes four parts: determining the output angles, computer simulation, explorations, model testing, and solutions. Provides a computer program and some diagrams. (YP)

The Long Duration Exposure Facility (LDEF) has been designed to take advantage of the two-way transportation capability of the space shuttle by providing a large number of economical opportunities for science and technology experiments that require modest electrical power and data processing while in space and which benefit from postflight…