Wavelength Measurements with a Concave Grating Spectrograph

Certain disadvantages and limitations in conventional methods of measuring wavelengths from grating spectrograms are discussed, and some alternative procedures described. It is shown that by fitting thorium standards to the dispersion of the Argonne 9.15-m spectrograph, using a polynomial least-squares program with a digital computer, wavelengths accurate to 1 in 108 can be obtained at a rate of 1000 per day.