An astrodome is a hemispherical transparent dome fitted in the cabin roof of an aircraft

Aircraft

An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

 to allow the use of a sextant

Sextant

A sextant is an instrument used to measure the angle between any two visible objects. Its primary use is to determine the angle between a celestial object and the horizon which is known as the altitude. Making this measurement is known as sighting the object, shooting the object, or taking a sight...

 during astro-navigation

Celestial navigation

Celestial navigation, also known as astronavigation, is a position fixing technique that has evolved over several thousand years to help sailors cross oceans without having to rely on estimated calculations, or dead reckoning, to know their position...

.

Prior to the introduction of electronic means

Radio navigation

Radio navigation or radionavigation is the application of radio frequencies to determine a position on the Earth. Like radiolocation, it is a type of radiodetermination.The basic principles are measurements from/to electric beacons, especially...

 of navigation

Navigation

Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...

 the only way to fix an aircraft's position at night was by taking star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

 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

Degree (angle)

A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians...

 view of the horizon

Horizon

The horizon is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not. At many locations, the true horizon is obscured by trees, buildings, mountains, etc., and the resulting...

 and the astrodome was devised to allow an uninterrupted view of the sky from horizon to horizon.

Astrodomes were prominent on Royal Air Force

Royal Air Force

The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...

 multi-engined aircraft of the Second World War, and on aircraft ordered by them, such as the Liberator

B-24 Liberator

The Consolidated B-24 Liberator was an American heavy bomber, designed by Consolidated Aircraft of San Diego, California. It was known within the company as the Model 32, and a small number of early models were sold under the name LB-30, for Land Bomber...

 and Dakota

C-47 Skytrain

The Douglas C-47 Skytrain or Dakota is a military transport aircraft that was developed from the Douglas DC-3 airliner. It was used extensively by the Allies during World War II and remained in front line operations through the 1950s with a few remaining in operation to this day.-Design and...

, as a considerable part of their operation

Military operation

Military operation is the coordinated military actions of a state in response to a developing situation. These actions are designed as a military plan to resolve the situation in the state's favor. Operations may be of combat or non-combat types, and are referred to by a code name for the purpose...

s and other flying were carried out at night.