... Us . ... Data . ... Nearly all FOS observations included an onboard target acquisition that used instrument observing modes to locate the science target in the desired aperture. ... No FOS acquisition exposure (e.g., an ACQ/BINARY exposure or a single scan-pattern of an ACQ/PEAK) could be interrupted by Earth occultation. ... As for ACQ/BIN, the first stage of a peak-up target acquisition was normally done in three integration steps with the 4.3" aperture and either the camera MIRROR or a disperser....