Sextant, Aircraft Periscopic, RAF Mk IIB, Ref No 6B/2838 Hughes The left dial selected the

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

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

The US Navy Anchor logo is stamped on the back and on the face is embossed "BU AERO US NAVY" (Bureau of Aeronautics)

The bottom knob controlled the turn

This is a Field Manual for the Identification of Japanese Aircraft published for US Military Intelligence by the War Department in March 1942

Sextant, Aircraft Periscopic, RAF Mk IIB, Ref No 6B/2838 Hughes The left dial selected theHere 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