"Ebsicon" is the generic name for any camera tube which contains a photoelectron-bombarded silicon diode array target. Following a description of the motivation for and the development of a large-format ebsicon (one containing an 80 mm photocathode and a 32 mm silicon target), the features of the device are presented. Emphasis is placed on the point-source performance of the tube in terms of the achieved point-source image cell density and the point-source response fall-off away from the center of the scanned area. Photocathode requirements are discussed in the context of the expected per-formance of the Air Force's upcoming Ground-based Electro-Optical Deep Space Surveillance (GEODSS) system. Then, field measurements for exposure times of 0.6 and 1/30 second, using G-type stars, are described and compared to the projected performance of a GEODSS electro-optical sensor. Finally, a list is presented of additional, important, and measured features of delivered, large-format ebsicons.