**LSQFIT** accepts the punched card fully reduced data and calculates a least-squares fitted polynomial curve of any specified order (to a maximum of six, in this case). Output is on cards, to be read as input by the programs in topic 2, which plot the curves and estimate the mean wavelength shift.

**GAUSSN** accepts the same data cards and calculates a least-squares fitted Gaussian curve, outputting parameters: mean wavelength shift, line depth and line width. Output is on cards, which are read by the program GAUSPT, a plotting program.