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Sea Astrolabe
The mariner's astrolabe, also called sea astrolabe, was an inclinometer used to determine the latitude of a ship at sea by measuring the sun's noon altitude (declination) or the meridian altitude of a star of known declination. Not an astrolabe proper, the mariner's astrolabe was rather a graduated circle with an alidade used to measure vertical angles. They were designed to allow for their use on boats in rough water and/or in heavy winds, which astrolabes are ill-equipped to handle. It was invented by the Portuguese people, a nation known for its maritime prowess and dominated the sea for multiple centuries. In the sixteenth century, the instrument was also called a ring. History Many dates can be found for the appearance of the first Mariner's astrolabes. The earliest date, 1295, is offered by the Majorcan astronomer Ramon Llull.''The Oxford Companion to Ships and the Sea'', Peter Kemp ed., 1976 Later dates center around the late 15th century, with Samuel Purchas clai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross Staff
The term Jacob's staff is used to refer to several things, also known as cross-staff, a ballastella, a fore-staff, a ballestilla, or a balestilha. In its most basic form, a Jacob's staff is a stick or pole with length markings; most staffs are much more complicated than that, and usually contain a number of measurement and stabilization features. The two most frequent uses are: * in astronomy and navigation for a simple device to measure angles, later replaced by the more precise sextants; * in surveying (and scientific fields that use surveying techniques, such as geology and ecology) for a vertical rod that penetrates or sits on the ground and supports a compass or other instrument. The simplest use of a Jacob's staff is to make qualitative judgements of the height and angle of an object relative to the user of the staff. In astronomy and navigation In navigation the instrument is also called a cross-staff and was used to determine angles, for instance the angle between the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graduation (instrument)
A graduation is a marking used to indicate points on a visual scale, which can be present on a container, a measuring device, or the axes of a line plot, usually one of many along a line or curve, each in the form of short line segments perpendicular to the line or curve. Often, some of these line segments are longer and marked with a numeral, such as every fifth or tenth graduation. The scale itself can be linear (the graduations are spaced at a constant distance apart) or nonlinear. Linear graduation of a scale occurs mainly (but not exclusively) on straight measuring devices, such as a rule or measuring tape, using units such as inches or millimetres. Graduations can also be spaced at varying spatial intervals, such as when using a logarithmic, for instance on a measuring cup, can vary in scale due to the container's non- cylindrical shape. Graduations along a curve Circular graduations of a scale occur on a circular arc or limb of an instrument. In some cases, non-ci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ivory
Ivory is a hard, white material from the tusks (traditionally from elephants) and teeth of animals, that consists mainly of dentine, one of the physical structures of teeth and tusks. The chemical structure of the teeth and tusks of mammals is the same, regardless of the species of origin, but ivory contains structures of mineralised collagen. The trade in certain teeth and tusks other than elephant is well established and widespread; therefore, "ivory" can correctly be used to describe any mammalian teeth or tusks of commercial interest which are large enough to be carved or scrimshawed. Besides natural ivory, ivory can also be produced synthetically, hence (unlike natural ivory) not requiring the retrieval of the material from animals. Tagua nuts can also be carved like ivory. The trade of finished goods of ivory products has its origins in the Indus Valley. Ivory is a main product that is seen in abundance and was used for trading in Harappan civilization. Finished ivor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brass
Brass is an alloy of copper (Cu) and zinc (Zn), in proportions which can be varied to achieve different mechanical, electrical, and chemical properties. It is a substitutional alloy: atoms of the two constituents may replace each other within the same crystal structure. Brass is similar to bronze, another copper alloy, that uses tin instead of zinc. Both bronze and brass may include small proportions of a range of other elements including arsenic (As), lead (Pb), phosphorus (P), aluminium (Al), manganese (Mn), and silicon (Si). Historically, the distinction between the two alloys has been less consistent and clear, and modern practice in museums and archaeology increasingly avoids both terms for historical objects in favor of the more general "copper alloy". Brass has long been a popular material for decoration due to its bright, gold-like appearance; being used for drawer pulls and doorknobs. It has also been widely used to make utensils because of its low melti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Journal Of Nautical Archaeology
The Nautical Archaeology Society (NAS) is a charity registered in England and WalesCharity Commission The Nautical Archaeology Society is registered charity number 264209 and in Scotland and is a company limited by guarantee.Companies house The Nautical Archaeology Society is registered at Companies House in England no. 1039270 The charitable aims and object of the company are to further research in and [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Esmeralda (carrack)
''Esmeralda'' was a Portuguese carrack () that sank in May 1503 off the coast of Oman as part of Vasco da Gama's 1502 Armada to India while commanded by da Gama's maternal uncle Vicente Sodré. First relocated in 1998 and excavated by David Mearns in 2013–15, is the earliest ship found, , from Europe’s Age of Discovery. Items recovered from the wreck site include the earliest known mariner's astrolabe The mariner's astrolabe, also called sea astrolabe, was an inclinometer used to determine the latitude of a ship at sea by measuring the sun's noon altitude (declination) or the meridian altitude of a star of known declination. Not an astrolabe ... believed to have been made between 1496 and 1501 and a ship's bell dated 1498. References {{Authority control Shipwrecks in the Arabian Sea 1503 in the Portuguese Empire Ships of Portugal Carracks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Mearns
David Louis Mearns, OAM, M.Sc. (born 10 August 1958), is an American-born United Kingdom based marine scientist and oceanographer, who specializes in deep water search and recovery operations, and the discovery of the location of historic shipwrecks. Early life Mearns was raised in Weehawken, New Jersey, where he attended Weehawken High School, graduating in 1976. He subsequently graduated B.Sc. in Marine Biology from Fairleigh Dickinson University in 1980, and obtained a Masters degree in Marine Geology from the University of South Florida in 1986. Oceanographic career From 1986 to 1995 Mearns was employed in the commercial undersea surveying industry in a managerial capacity. In 1990 he worked on the criminal investigation into the foundering of the freighter '' Lucona'', and in 1994 located the wreck of the ore-bulk-oil carrier . Relocating to England in the mid 1990s, he established ''Blue Water Recoveries, Limited'', a commercial company that locates and researches histo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Esteban (1554 Shipwreck)
''San Esteban'' was a Spanish cargo ship that was wrecked in a storm in the Gulf of Mexico on what is now the Padre Island National Seashore in southern Texas on 29 April 1554. ''San Esteban'' was one of a flotilla of four ships carrying treasure from New Spain (Mexico) to Cuba. Three were wrecked in the storm, including ''San Esteban''. Many of the three hundred sailors and passengers drowned while trying to reach shore. About thirty took a boat to seek help. Almost all the others died of thirst or starvation, or were killed by hostile local Karankawa Indians during their attempt to walk back to safety. The Spanish sent a salvage expedition, but recovered less than half of the cargo and treasure. One of the wrecks was rediscovered in 1964. A private company, Platoro, Ltd., began to excavate the Espíritu Santo wreck in late 1967, which caused public outrage and the passage of new laws to protect wrecks on the Texan coast. The remains of ''San Esteban'' were found in 1970 and e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corpus Christi Museum Of Science And History
The Corpus Christi Museum of Science and History is a science and history museum in Corpus Christi, Texas, near Corpus Christi Harbor Bridge The Corpus Christi Harbor Bridge is a through arch bridge located in Corpus Christi, Texas which carries six lanes of U.S. Route 181 (US 181) and Texas State Highway 35 (SH 35) from downtown Corpus Christi to Rincon Point, known to local ... and the waterfront. It was established in 1957. Among its many displays covering an area of over 40,000 square feet are many artifacts found in the wreck of the Spanish ship '' San Estaban'', including the world's oldest mariner's astrolabe with a confirmed date of 1554. An extension to the museum opened in May 1990 to house the ''Shipwreck!'' exhibition. References External linksOfficial site {{coord, 27, 48, 37, N, 97, 23, 42, W, type:landmark, display=title Science museums in Texas History museums in Texas Buildings and structures in Corpus Christi, Texas Museums established in 195 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite systems (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephonic or Internet reception, though these technologies can enhance the usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls and maintains the GPS system, it is freely accessible to anyone with a GPS receiver. The GPS project was started by the U.S. Department of Defense in 1973. The first prototype spacecraft was lau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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