Abstract

The limitations of conventional Schlieren systems are discussed briefly. A system replacing the point source of light with a grid of pinholes, and the knife edge with a negative image of the grid is presented as a means of overcoming these limitations. A simple apparatus using this system is described, and methods of preparing and adjusting the grids are discussed. A photograph of air jets is presented as experimental evidence of the sensitivity of the apparatus. It is concluded that the apparatus is adaptable to large areas of field as the field is not dependent on lens size as with conventional systems; instead, it is determined only by the size of the easily prepared grid. Added advantages of this system are that a point source of light is not required, and, as a result of a depth of field effect, undesirable striations along the optical path do not interfere with the images being studied.

© 1949 Optical Society of America

Interference Phenomenon in the Schlieren System*

E. L. Gayhart and Rochelle Prescott
J. Opt. Soc. Am. 39(7) 546-550 (1949)

Camera Shutters*

Amrom H. Katz
J. Opt. Soc. Am. 39(1) 1-21 (1949)

A Method of Measuring High Intensities at the Focus of a Parabolic Reflector with Large Relative Aperture

George E. Davis
J. Opt. Soc. Am. 39(7) 541-543 (1949)

A Photoelectric Reflection-Transmission Densitometer

R. L. Huber and A. B. Rakus
J. Opt. Soc. Am. 39(10) 873-876 (1949)

Some Variables Influencing Vernier AcuityI. Illumination and Exposure TimeII. Wave-Length of Illumination*

Katherine Eleanor Baker
J. Opt. Soc. Am. 39(7) 567-576 (1949)