Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another. The field of navigation includes four general categories: land navigation, marine navigation, aeronautic navigation, and space navigation.
A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation.
An astrolabe is an astronomical instrument dating to ancient times. It serves as a star chart and physical model of visible heavenly bodies. Its various functions also make it an elaborate inclinometer and an analog calculation device capable of working out several kinds of problems in astronomy. In its simplest form it is a metal disc with a pattern of wires, cutouts, and perforations that allows a user to calculate astronomical positions precisely. It is able to measure the altitude above the horizon of a celestial body, day or night; it can be used to identify stars or planets, to determine local latitude given local time, to survey, or to triangulate. It was used in classical antiquity, the Islamic Golden Age, the European Middle Ages and the Age of Discovery for all these purposes.
An alidade or a turning board is a device that allows one to sight a distant object and use the line of sight to perform a task. This task can be, for example, to triangulate a scale map on site using a plane table drawing of intersecting lines in the direction of the object from two or more points or to measure the angle and horizontal distance to the object from some reference point's polar measurement. Angles measured can be horizontal, vertical or in any chosen plane.
The backstaff is a navigational instrument that was used to measure the altitude of a celestial body, in particular the Sun or Moon. When observing the Sun, users kept the Sun to their back and observed the shadow cast by the upper vane on a horizon vane. It was invented by the English navigator John Davis, who described it in his book Seaman's Secrets in 1594.
Navigational instruments are instruments used by nautical navigators and pilots as tools of their trade. The purpose of navigation is to ascertain the present position and to determine the speed, direction, etc. to arrive at the port or point of destination.
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:
The octant, also called a reflecting quadrant, is a reflecting instrument used in navigation.
In astronomy, sextants are devices depicting a sixth of a circle, used primarily for measuring the position of stars. There are two types of astronomical sextants, mural instruments and frame-based instruments.
A quadrant is an instrument used to measure angles up to 90°. Different versions of this instrument could be used to calculate various readings, such as longitude, latitude, and time of day. Its earliest recorded usage was in ancient India in Rigvedic times by Rishi Atri to observe a solar eclipse. It was then proposed by Ptolemy as a better kind of astrolabe. Several different variations of the instrument were later produced by medieval Muslim astronomers. Mural quadrants were important astronomical instruments in 18th-century European observatories, establishing a use for positional astronomy.
An Elton's quadrant is a derivative of the Davis quadrant. It adds an index arm and artificial horizon to the instrument, and was invented by English sea captain John Elton, who patented his design in 1728 and published details of the instrument in the Philosophical Transactions of the Royal Society in 1732.
David Louis Mearns, OAM, 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.
A sine quadrant, sometimes known as a "sinecal quadrant", was a type of quadrant used by medieval Arabic astronomers. The instrument could be used to measure celestial angles, tell time, find directions, perform trigonometric computations, and determine the apparent positions of any celestial object for any time. The name is derived from the Arabic rub meaning 'a quarter' and mujayyab meaning 'marked with sine'.
Astronomical rings, also known as Gemma's rings, are an early astronomical instrument. The instrument consists of three rings, representing the celestial equator, declination, and the meridian.
The shadow square, also known as an altitude scale, was an instrument used to determine the linear height of an object, in conjunction with the alidade, for angular observations. An early example was described in an Arabic treatise likely dating to 9th or 10th-century Baghdad. Shadow squares are often found on the backs of astrolabes.
Shadows is a software package for the calculation and drawing of sundials and astrolabes, available as a freeware in its base level.
Vicente Sodré was a 16th-century Anglo Portuguese knight of Order of Christ and the captain of the first Portuguese naval patrol in the Indian Ocean. He was an uncle of Portuguese explorer Vasco da Gama.
Throughout the early age of exploration, it became increasingly clear that the residents of the Iberian Peninsula were experts at navigation, sailing, and expansion. From Henry the Navigator's first adventures down the African coast to Columbus's fabled expedition resulting in the discovery of the new world, the figures that catalyzed the European appetite for expansion and imperialism heralded from either Spain or Portugal. However, merely a century earlier, nautical travel for most peoples was resigned to keeping within sight of a coastline and very rarely did ships venture out into deeper waters. The period's ships were not able to handle the forces of open ocean travel and the crewmen had neither the ability nor the necessary materials to keep themselves from getting lost. A sailor's ability to travel was dictated by the technology available, and it was not until the late 15th century that the development of the nautical sciences on the Iberian Peninsula allowed for the genesis of long-distance shipping by directly effecting, and leading to the creation of, new tools and techniques relative to navigation. Christopher Columbus’s famous expedition, which crossed the ocean in 1492, was arguably the first contact the civilized world had with the newly discovered continent. Financed and sponsored by Queen Isabella of Spain, his journey would open the door to new trading lanes, imperialist appetites, and the meeting of cultures. Portugal and Spain became the world's foremost leaders in deep water navigation and discovery because of their sailing expertise and the advancement of nautical sciences benefiting their ability to sail further, faster, more accurately, and safer than other states. Vast amounts of precious minerals and lucrative slaves were poured into Iberian treasuries between the late 15th and mid to late 17th centuries because of Spanish and Portuguese domination of Atlantic trade routes. The golden age of Spain was a direct result of the advancements made in navigation technology and the sciences which allowed for deep water sailing.
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, as of 2016, from Europe's Age of Discovery.
