<nowiki>Orbiting Astronomical Observatory; Orbiting Astronomical Observatory; Орбитальная астрономическая обсерватория; Orbiting Astronomical Observatory; Orbiting Astronomical Observatory; Orbiting Astronomical Observatory 3; 軌道天文台; 軌道天文台; Орбитална астрономска опсерваторија; Uydusal Astronomik Gözlemevi; OAO; Orbiting Astronomical Observatory; Orbiting Astronomical Observatory; อุปกรณ์สังเกตการณ์ดาราศาสตร์ในวงโคจร; Orbitalne Obserwatoria Astronomiczne; מצפה כוכבים מסלולי; Ebe Na-enyocha Ihe Ndị Dị na Ụzọ Mmiri; 軌道天文台; Orbiting Astronomical Observatory; Orbiting Astronomical Observatory; 천체관측위성; Orbiting Astronomical Observatory; مرصد فلكي مداري; 轨道天文台; Orbiting Astronomical Observatory; серия из четырёх спутников-обсерваторий; Serie von vier Weltraumteleskopen der NASA; series of four space observatories launched between 1966 and 1972; programme de la NASA; amerikai csillagászati műhold; OAO; مرصد المدار الفلكي; Copernicus Observatory; OAO; ОАО</nowiki>
Orbiting Astronomical Observatory
series of four space observatories launched between 1966 and 1972
