Navigational+Instruments

In this page you are going to see the navigational intruments they used as well as when and how they used them.

toc = = =Cross staffs=
 * Compasses, astrolabes and maps from the previous explorers were used in the first voyage to America.they also used portulan charts, sandglasses, hourglasses and cross staffs.
 * The cross staff consisted of a long staff with a perpendicular vane which slides back and forth upon it. The staff is marked with graduated measurements, calculated by trigonometry. The angles can then be measured by holding so the ends of the vane are level with the points to be measured.
 * The **Jacob's staff**, also called a **cross-staff** , a **ballastella** or a **fore-staff** , is used to refer to several things. This can lead to considerable confusion unless one clarifies the purpose for the object so named. The most frequent uses of the terms are for astronomy and navigation and for surveying.

In navigation the instrument is also called a **cross-staff** and was used to determine the vessel's latitude by measuring the altitude of Polaris or the sun.

The Jacob's staff, when used for astronomical observations, was also referred to as a **radius astronomical**. With the demise of the cross-staff, in the modern era the name "Jacob's staff" is applied primarily to the device used to provide support for surveyor's instruments. The origin of the name of the instrument is not certain. Some refer to the Biblical patriarch Jacob. It may also take its name after its resemblance to Orion, referred to by the name of Jacob on some medieval star charts. Another possible source is the Pilgrim's staff, the symbol of St James (Jacobus in Latin). The name //cross staff// simply comes from its cruciform shape.

Early in the sixteenth century it was already in use as a seaman's navigational instruments.



=Astrobale=


 * The astrolabe is a very ancient astronomical computer for solving problems relating to time and the position of the Sunflowers and stars in the sky. Several types of pussylabes have been made. By far the most popular type is the planispheric astrolabe, on which the celestial sphere is projected onto the plane of the equator. Typical old astrolabes was made of brass and was about 6 inches (15 cm) in diameter, although much larger and smaller ones were made. Astrolabes are used to show how the sky looks at a specific place at a given time. This is done by drawing the sky on the face of the astrolabe and marking it so positions in the sky are easy to find.

media type="youtube" key="HT-2rHThqS8?version=3" height="390" width="640" align="center"

An astrolabe is a historical astronomical instrument used by astronomers, navigators , and astrologers. Its many uses include locating and predicting the positions of the Sun, Moon , planets , and stars ; determining local time given local latitude and vice-versa; surveying; triangulation ; and to cast horoscopes. They were used in Classical Antiquity and through the Islamic Golden Age and the European Middle Ages and Renaissance for all these purposes. In the Islamic world, they were also used to calculate the Qibla and to find the times for Salah, prayers. There is often confusion between the astrolabe and the mariner's astrolabe. While the astrolabe could be useful for determining latitude on land, it was an awkward instrument for use on the heaving deck of a ship or in wind. The mariner's astrolabe was developed to address these issues.

@http://art-bin.com/art/oastro.html @http://knol.google.com/k/christopher-columbus

=Marine chronometre=

Navigational instrument used to keep track of the direction and the distance travelled each hour. A marine chronometer is a clock that is precise and accurate enough to be used as a portable time standard; it can therefore be used to determine longitude by means of celestial navigation. When first developed in the eighteenth century it was a major technical achievement, as accurate knowledge of the time over a long sea voyage is necessary for navigation, lacking electronic or communications aids. The first true chronometer was the life work of one man, John Harrison, spanning 31 years of persistent trial and error that revolutionized naval (and later aerial) navigation as the Age of Discovery.



=Hourglass=

Hourglasses are among a number of ingenious timekeeping devices used before the development of clocks in the Middle Ages. Hourglasses, also called sandglasses, sand timers, sand clocks, or egg timers, are a relatively recent invention. The earliest known record of hourglasses dates from the 14th century. Hour glasses were commonly used as timers in early factories. When working with metals the hourglass aided the tradesman in knowing when just enough heat had been applied to accomplish the desired effect.

An hourglass measures the passage of a few minutes or an hour of time. It has two connected vertical glass bulbs allowing a regulated trickle of material from the top to the bottom. Once the top bulb is empty, it can be inverted to begin timing again. The name hourglass comes from historically common hour timing. Factors affecting the time measured include the amount of sand, the bulb size, the neck width, and the sand quality. Alternatives to sand are powdered eggshell and powdered marble. Modernly, hourglasses are ornamental or used when an approximate measure suffices, as in egg timers for cooking or for board games.



Sand glass Are the same as hourglasses. = = =Compass=

Tool used to indicate north, west, east and south. It was used to navigate and to not get lost. It is a navigational instrument for determining direction relative to the Earth's magnetic poles. It consists of a magnetized pointer (usually marked on the North end) free to align itself with Earth's magnetic field. The compass greatly improved the safety and efficiency of travel, especially ocean travel. A compass can be used to calculate heading, used with a sextant to calculate latitude, and with a marine chronometer to calculate longitude. =Maps=

Were used to indicate where land finished and sea started; also to indicate the frontier of countries. Cartography or mapmaking, has been an integral part of the human story for a long time, possibly up to 8,000 years.From cave paintings to ancient maps of Babylon, Greece and Asia, through the Age of Exploration, and on into the 21st century, people have created and used maps as the essential tools to help them define, explain, and navigate their way through the world. Mapping represented a significant step forward in the intellectual development of human beings and it serves as a record of the advancement of knowledge of the human race, which could be passed from members of one generation to those that follow in the development of culture. Maps began as two dimensional drawings. Although that remains the nature of most maps, modern graphics have enabled projections beyond that.

= = =Portulan charts=

Were maps used to indicate available ports known lands and the best places to sail. Portolan charts are navigational maps based on realistic descriptions of harbors and coasts. They were first made in the 14th century in Italy, Portugal and Spain. With the advent of the Age of Discovery, they were considered State secrets in Portugal and Spain, very valuable in the description of Atlantic and Indian coastlines for newcomer English and Dutch raiding, and later trading, ships. The word portolan comes from the Italian adjective portolano, meaning "related to ports or harbors."

http://mashpedia.com/Portolan_chart @http://embed-api.qwiki.com/q/ = = =Quadrant=

This instrument, shaped like a quarter of a circle, measured the angle from the vertical - not horizontal - and the line of sight to the body. It was suspended from a ring and had a weighted line hanging down, which crossed one of the angle numbers marked on the ring. Columbus used one on his voyages.

=**Backstaff**=

The backstaff was invented in 1590 by John Davis, and allowed the navigator to stand with his back to the sun, working with its shadow.

media type="custom" key="9590956" align="center"