These are examples of developmental image tubes (vidicons) that John Lowrance made for RCA in the early 1970s. Vidicons provided electronic imaging capabilities for space telescope applications, notably for the Hubble Space Telescope. This specific example, the larger of the two in the images, is an RCA model C21180. It employed a secondary emission cathode design with a silicon intensified target (SIT). The specific object is labelled I-SIT-ISOCON #6S01029 and is dated 9/24/73. It is one of several examples accessioned from John Lowrance's company that represent the state of the art for this class of detector at the time NASA decided to switch from this technology to solid state CCD detectors for the Wide Field Planetary Camera.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.