Night Vision Goggles
Night glasses are telescopes or binoculars with a large diameter objective. Large lenses can gather and concentrate light, thus intensifying light with purely optical means and enabling the user to see better in the dark than with the naked eye alone. Often night glasses also have a fairly large exit pupil of 7 mm or more to let all gathered light into the user's eye. However, many people can't take advantage of this because of the limited dilation of the human pupil. To overcome this, soldiers were sometimes issued atropine eye drops to dilate pupils. Before the introduction of image intensifiers, night glasses were the only method of night vision, and thus were widely utilized, especially at sea. Second World War era night glasses usually had a lens diameter of 56 mm or more with magnification of seven or eight. Major drawbacks of night glasses are their large size and weight.
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Famous quotes containing the words night and/or vision:
“‘Tis said of love that it sometimes goes, sometimes flies; runs with one, walks gravely with another; turns a third into ice, and sets a fourth in a flame: it wounds one, another it kills: like lightning it begins and ends in the same moment: it makes that fort yield at night which it besieged but in the morning; for there is no force able to resist it.”
—Miguel De Cervantes (1547–1616)
“And taken by light in her arms at long and dear last
I may without fail
Suffer the first vision that set fire to the stars.”
—Dylan Thomas (1914–1953)