Astrodome (aeronautics)

The astrodome (arrowed) on a Warwick B/ASR Mk 1

An astrodome is a hemispherical transparent dome fitted in the cabin roof of an aircraft to allow the use of a sextant during astro-navigation.

Prior to the introduction of electronic means of navigation the only way to fix an aircraft's position at night was by taking star sights using a sextant in the same manner as that used by marine navigators for hundreds of years on board ships. To do this requires a 360-degree view of the horizon and the astrodome was devised to allow an uninterrupted view of the sky from horizon to horizon.

Astrodomes were prominent on many Royal Air Force (RAF) and Commonwealth operated multi-engined aircraft of the Second World War, and on foreign aircraft ordered by them for their use, such as the Liberator and Dakota, as a considerable part of the RAF's operations and other flying were carried out at night.

Later use on ocean-racing yachts

In the 1950's and 60"s, astrodomes were gradually phased out, as radionavigation and ground plotting radars took over, but enjoyed a second career on ocean racing yachts (specially in singlehanded racing). Eric Tabarly, record-breaking winner of the 1964 OSTAR singlhanded transatlantic race, and former french Aéronavale (Fleet air arm) pilot, had fitted lis revolutionary lightweight ketch-rigged racer Pen Duick II with an astrodome scavenged from a Shorts Sunderland decomissioned aircraft.

Not only could he use it for sextant astro-navigation, but it provided a sheltered place from where he could steer his yacht during a stormy race, quite a useful help as his wind-vane autopliot (also of aéronautical technology) had broken down.