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an astronomical instrument for taking the altitude of the sun or stars and for the solution of other problems in astronomy and navigation: used by Greek astronomers from about 200 b.c. and by Arab astronomers from the Middle Ages until superseded by the sextant.
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How did the astrolable help sailers?
The astrolable was helpful because it was a instrument used for measuring the positions of the stars- Reno09
When was the astrolable invented?
Around 145O (:
How did an astrolable help explorers?
Navigational aid to determine longitude
The astrolable was associated with?
It is an astronomical instrument for taking the altitude of the sun or stars
What changes in technology helped set the stage for Europeans exploration?
do you go to ivy academia. the astrolable and the compass
What were Muslims major contributions in the areas of science math medicine and art?
The Muslim developed a distinct form of art based on Islam. Muslims made important innovations in mathematics. Later, they passed on these on discover to Europeans. For example, Muslims invented algebra, a type of mathematics still taught in school todays. the Arabs also borrowed the symbols 0 through 9 from Hindu school in India. These number were later used by Europeans. Today, they are known as " Arabic numerals". Muslims also made progress in science. Muslim scientists who studied the heavens perfected the Greek astrolable.
What are some things that are used for celestial navigation?
Astral navigation, no matter what instrument was used, involves measuring angles of the sun or stars with respect to a reference line. For seafarers, the astrolabe -- specifically, the mariner's astrolabe -- is an ancient tool for navigating by the sun or stars. Unlike the common astrolable, the mariner's version was designed to be used somewhat more easily on rough seas or high winds. It was not particularly accurate, but it served the purpose. The simple quadrant operated on a different and somewhat more advanced principle than the astrolabe. The name referred to the device's ability to measure up to 90 degrees, a quarter of a circle. It used a plumb line (a weighted string or wire) as the vertical reference and measured the altitude of the celestial body with respect to the line. The sextant was designed to measure the angle between the sun or a star and an external reference such as the horizon. It was far more accurate than measuring the angle between the body and the instrument itself, which is how the astrolabe and the quadrant worked. The name refers to the scale's length being 1/6th of a circle. The octant is a variation of the sextant with a scale that is 1/8th of a circle. All of them assume that the navigator has a deep knowledge of the astronomical references such as sun's position or the locations of specific stars at every day of the year, or has a detailed book of tables. The A competent navigator can determine latitude easily, and with an accurate clock can also determine longitude. Although GPS has largely replaced the sextant as a necessary instrument, the sextant is still widely used for nautical navigation, if only by sea-loving diehards and purists, or as backups if the batteries in the Garmin die. They have become quite complex, but they still use ancient principles. For the sextant user, the US Naval Observatory issues "The Nautical Almanac" that gives all the data needed for accurate navigation by the sun or stars. Wikipedia has a series of articles on the various devices. Google the names and look for the Wiki pages.
