90prime is a prime focus wide-field imager for the Steward Observatory 90" telescope. The optical design includes a four element corrector and six position filter wheel. The focal plane array is a mosaic of four Lockheed 4k x 4k CCDs which have been thinned for back illumination by the University of Arizona Imaging Technology Laboratory.

The camera will provide an imaging area of 1.0 square degrees. The edge-to-edge field-of-view including the inter-CCD spacing is 1.16° x 1.16° with a plate scale of 30.2"/mm or 0.45"/pixel. The instrument is currently available for shared risk observing.