Abstract: This relates to an image interpretation instrument including a viewing head and a carriage for supporting imagery. A table provides support for a base, such as a map. The head and the carriage are movable from a first position wherein an observer views both the base and the imagery on the carriage and can thus annotate the base with information derived from the imagery, to a second position wherein the observer views only the imagery and can annotate the imagery directly. Attachment devices for the viewing head are described which permit the viewing of a variety of types of imagery.