The ~1100 spectra dispersed by OASIS are imaged onto a 2k x 4k deep-depletion MIT/LL CCD. This CCD has high quantum efficiency (~0.9 at 0.75 microns) and low readout noise (2.3 electrons rms in slow readout mode and 2.8 electrons in fast), and will remain on OASIS indefinitely.

The fringing level is low. When the detector was mounted on the Cassegrain spectrograph ISIS, fringing was measured to be ~3% at 0.8 microns and ~ 10% peak-to-peak at 1 micron.