Optical
In World War II, a height finder was an optical rangefinder used to determine the altitude of an aircraft (actually the slant range from the emplacement which was combined with the angle of sight, in a mechanical computer, to produce altitude), used to direct anti-aircraft guns. Examples of American and Japanese versions exist, in the Soviet Union it was usually combined with optical rangefinders, certainly a German version exist.
Read more about this topic: Height Finder
Famous quotes containing the word optical:
“It is said that a carpenter building a summer hotel here ... declared that one very clear day he picked out a ship coming into Portland Harbor and could distinctly see that its cargo was West Indian rum. A county historian avers that it was probably an optical delusion, the result of looking so often through a glass in common use in those days.”
—For the State of New Hampshire, U.S. public relief program (1935-1943)
“The convent, which belongs to the West as it does to the East, to antiquity as it does to the present time, to Buddhism and Muhammadanism as it does to Christianity, is one of the optical devices whereby man gains a glimpse of infinity.”
—Victor Hugo (1802–1885)
“There is an optical illusion about every person we meet.”
—Ralph Waldo Emerson (1803–1882)