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Optical equipmentOptical instruments comprise three main groups: telescopes, binoculars and rangefinders. Browse the entire collection or: View by:
About this collectionOptical instruments comprise three main groups: telescopes, binoculars and rangefinders. The National Maritime Museum has over 360 telescopes in its collection. These include both hand-held telescopes for making observations at sea or on land and those designed for astronomical use. The telescopes date from the mid-17th to the 20th century and were mostly made in Europe. The majority of the collection consists of refracting telescopes, which use lenses to gather light from the object being viewed. Early examples suffered from chromatic aberration – the appearance of coloured fringes around objects, caused by light being split into its component colours as it passes through the lens. The development of the achromatic lens in the mid-18th century reduced this problem and many of the telescopes in the Museum contain these lenses. A number of the astronomical telescopes are reflecting telescopes, which use a curved mirror to gather light. The use of mirrors instead of lenses was another way to avoid chromatic aberration. The Museum has a small collection of binoculars dating from the mid-19th to the mid-20th century. Binoculars were first made in the 17th century, but were only fully developed from the 1820s, when Johann Voigtländer, an optician in Vienna, began producing binocular telescopes. The first prismatic telescopes were made in the 1870s, and it was these that largely replaced hand-held telescopes in the 20th century. The rangefinders and distance meters in the Museum are mainly those that mariners used for determining the distance to another vessel or to an object on land. These could also be used for station-keeping – maintaining the correct distance relative to other vessels when sailing in company or in convoy. Larger rangefinders were also used in gunnery, but are not part of the Museum collection. Includes telescopes, binoculars, rangefinders. |
