2. who invented the map on which the astrolabe is based on

The universal astrolabe was a major breakthrough because it could be used at any location. Ordinary astrolabes needed different latitude plates if they were moved, because they were designed for a certain place and were latitude dependent.

An important aspect of the universal astrolabe was that its stereographic projection used the vernal or autumnal equinox as the center of projection onto the plane of the solstitial colure.

There are, of course other types of astrolabe such as Nautical, Quadrant, Rojas Astrolabes, and Planispheric Astrolabe was one of the most popular one. Other one of the most interesting of them all was an astrolabe with geared calendar made by Muhammad b. Muhammad ibn Abi Bakr al-Farisi d. This early Persian astrolabe with a geared calendar movement is the oldest geared machine in existence in a complete state.

It illustrates an important stage in the development of the various complex astronomical machines from which the mechanical clock derives. These phenomena were of fundamental importance in the lunar calendar used in Muslim Civilisation. The astrolabe is an instrument maximum size, usable size, that we have and most people can see in museums etc. It is in the order of maybe inches, they are all in that range. It is really a series of brass discs turning one on top of each other.

You can manage to solve with all sorts of mathematical problems. The same Abdul Rahman al-Sufi, who worked on the stars, also wrote a book on the construction and use of an astrolabe. He gave us the list of astronomical mathematical problems that could be solved with an astrolabe. Put briefly to our modern use and to our young people nowadays, it is nothing different, it is in change of function, it is just as efficient as your little pocket calculator that you use nowadays.

Unfortunately nowadays most kids in schools use it to find the sum function and to multiply functions, which is what an astrolabe does. It is an ingenious application of mathematics onto a technology that allows you to solve mathematical problems. Astrolabes were the cutting edge of technology, used and developed by astronomers in Muslim Civilisation who were intrigued and fascinated by the heavens. It was through these hardworking scholars that the astrolabe made it into Europe, where modern astronomy was born.

Dagger-shaped pointers were characteristic of early astrolabes from Muslim Civilisation. Each plate has engraved on it a grid marking the zenith point directly over head , the horizon and all the altitudes in between;. It was not so different in medieval times, there are manuscripts or books show how to use or construct various Astrolabes. It was composed by Najm al-D n al-Misr , a rather shadowy figure, in Cairo ca. We would like to finish our story with what he wrote to his son:.

Little Lewis my son, I have. And with this little treatise, I propose to teach you some conclusions pertaining to the same instrument. Today, this somewhat-scientific, somewhat-mystical device leaves its traces in modern analog gadgets like a slide rule or the fanciest Swiss watches.

One is Owen Gingerich , a professor emeritus of astronomy and the history of science at Harvard University. He first became interested in astrolabes when a student presented one to him in his office years ago, offering to sell this family treasure in order to help fund a medical clinic back home in Afghanistan. When the student offered to sell it, Gingerich obliged, with plans to use it as a teaching tool.

This got me going on them. While devices from different regions and time periods could vary widely—depending on their intended purpose and who made them, they could be as small as a coffee saucer or as large as a trash can lid, and made out of anything from wood to brass—they shared a similar structure. Over that, a straight rule pivots around to line up with time measurements along the edge of the mater. And on the back of the whole thing, a pivotable siting device helps find the altitude of a star—often the starting point of a calculation.

Because the geography of the sky changes with your latitude, astrolabes commonly came with a series of plates associated with different latitudes of large cities.

And though they could have been made out of a variety of materials, the majority that remain intact today are made of brass, very ornate, and are often associated with the educated elite, says Gingerich. Still, while very fancy astrolabes remain today, there were likely plenty of others created for more ordinary people that have since rotten away if made of wood or gotten thrown back into the melting pot if they were made of metal, says Alexander Jones, a researcher at New York University and an expert in ancient astronomy.

That job took many forms. Astrolabes had blended uses, from scientific to what we would today consider spiritual. They have a strong history in Islam as a tool to find both the direction of prayer toward Mecca—known as the Qibla—as well as the five times of prayer required throughout the day, as stated in the Quran. A number of Greek scholars wrote in-depth treatises and texts on the astrolabe. Eventually, the tool was introduced to scholars in the Islamic world.

They soon started using the instrument, mainly for navigation, and wrote many texts on the instrument themselves. Texts were also written on the subject in India, showing the extent to which this tool was used around the world. The mater is marked indicating hours, degrees, or both measurements. The rete is the actual map of the ecliptic plane and has several pointers to indicate the brightest stars.

You can think of the rete as a star chart. Often, different scales are engraved on the back of the mater to help in calculations.