The ultraviolet spectrometers that observed the atmosphere of Mars in July and August of 1969 consist of a planetary coronagraph and an Ebert-Fastie monochromator. The spectral range 1100-4300 A was measured using two photomultiplier tubes, one with a cesium iodide photocathode, the other with a bialkali photocathode. These tubes were operated with fixed high voltage supplies and charge sensitive amplifiers. The instruments were calibrated by comparison with a tungsten lamp, a sodium salicylate screen, and a flowing nitric oxide cell. The instruments were able to satisfactorily reject off-axis light at a distance of 6600 km and measure the emission spectrum of the upper atmosphere 170 km above the surface.