Description:This is a convenient setup for showing the visible spectrum. A bright point source is used to provide a continuous white light spectrum. Light from the point source is focused first by an integral condenser lens and iris and then a 20cm focal length convex cylindrical lens onto an adjustable slit. A 20cm focal length convex spherical lens then images the slit through an equilateral flint glass prism onto a screen.
For mechanical drawings of the original point source, see lecdem.physics.umd.edu/images/Demos/point%20source%20plans.pdf