The total column abundance of NO3 was measured in Antarctica during the nights of September 17--19, 1986, by visible absorption, using the moon as the light source. The variation of the observed abundance with lunar zenith angle suggests that the bulk of the layer is located in the stratosphere. In agreement with theoretical model calculations, the total column was about 2.0¿1013 molecule cm-2 and increased systematically with time during the night. ¿ American Geophysical Union 1987