The technical note is one of a series that provides brief descriptions of scientific programs investigating the physics and chemistry of the upper atmosphere under normal and disturbed conditions in support of the High Altitude Effects Simulation HAES program of the Defense Nuclear Agency. In the absence of actual nuclear testing in the atmosphere a number of experiments are being carried out both in the laboratory and in the field to determine a sufficient number of parameters to characterize the environment and its reactions in a suitable model. This technical note describes one of these experiments. The circular variable filter CVF infrared spectrometer is one of the principal instruments used in rocket-borne experiments to measure auroral infrared emissions. The spectrometers described were developed by Utah State University and include both liquid nitrogen cooled short wavelength infrared and liquid helium cooled long wave infrared spectrometers. A brief description is also given of the CVF spectrometer experiments flown in the ICECAP 73 rocket series launched from Poker Flat, Alaska in March 1973.