The optical and electronic design of the Halogen Occultation Experiment (HALOE) elevation sun sensor is described. The HALOE instrument is a gas-correlation radiometer now being developed by NASA Langley Research Center for the Upper Atmosphere Research Satellite (UARS). The system uses a Galilean telescope to form a solar image on a linear silicon photodiode array. The array is a self-scanned monolithic charge-coupled device. The addresses of both solar edges imaged on the array are used by the control/pointing system to scan the HALOE science instantaneous field of view (IFOV) across the vertical solar diameter during instrument calibration and then to maintain the science IFOV 4 arcmin below the top edge during the science data occultation event. Vertical resolution of 16 arcsec and a radiometric dynamic range of 100 are achieved at the 0.7 µm operating wavelength. The design provides for loss of individual photodiode elements without loss of angular tracking capability.