As an expression, a "close encounter" is used to qualify a contact with some type of foreign entity associated with the UFO phenomenon. In principle its creator Josef Allen Hynek classified it in : First Type , for the sighting of objects less than 150 meters; Second Type , when the object leaves recognizable marks of its passage; and Third Type, when an animated presence is observed. Then more types and subtypes were added for more specific cases. The name is a translation of English close encounter . View Blue Book ( US Project ) .