Sextant, Aircraft Periscopic, RAF Mk IIB, Ref No 6B/2838 Hughes It may be some sort

It may be some sort of a stall warning instrument

(approx 11 inches by 9 inches) containing maps and geographical reference information regarding the Japanese Empire circa 1943

The left dial selected the spacing interval between bombs at a given airspeed

which was indicated on the top gauge on the indicator

The cover is a thick index card stock which covers 55 pages

Sextant, Aircraft Periscopic, RAF Mk IIB, Ref No 6B/2838 Hughes It may be some sortHere is an original aircraft Periscopic Sextant Mk IIB as used in aircraft of the British Royal Air Force, in its original carrying case. The periscopic sextant was used in aircraft with a pressurized cabin, whereas the 'periscope' was inserted through a shutter mounted in the ceiling of the aircraft. This provided an unobstructed view of the sky for celestial navigation without compromising the pressurization of the crew cabin. The serial number of