#observation bubble
- Astrodome — A transparent, hemispherical dome or cupola made of optical glass or durable plexiglass, mounted on the upper fuselage of an aircraft (especially 20th-century bombers and transport planes) or on a terrestrial structure. This structural element allowed the flight navigator to use a sextant or astrocompass to determine the position by observing celestial bodies, while in architecture it designates the rotating dome of a small astronomical observatory.