A Birefringent Monochromator for Isolating High Orders in Grating Spectra

A modified quartz Šolc filter, designed to isolate a single high order of a coarse grating, has proved to be a simple and convenient accessory for solar spectrography. It transmits unpolarized light, diminished only by absorption and reflection losses in the material, has a wide choice of bandwidth, and is tunable to any wavelength transmitted by the optical materials. This monochromator is used like an ordinary glass filter by simply placing it in front of the spectrograph slit. Its principles of operation and construction are described.