To film very stable exerior IMAX footage, astronauts mounted the 2-D IMAX camera on this aluminum bracket which attached to the Space Shuttle's flight deck overhead windows. Small pins along the interior ring allowed the placement of the ring on the camera and then attachment of the camera to the larger bracket installed around the window. A black fabric shroud could be attached around this bracket to shield the camera's lens from ambient light in the cabin.
NASA transferred this brack along with other IMAX equipment to the Smithsonian in 2012.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.