Astrolabe

Hello there,

I was in search of some interesting TED videos, when I stumbled upon Tom Wujec's presentation on the Astrolabe, an ancient astronomical device capable to do many things, like timekeeping, predicting planetary movements, as well as of the sun and moon.

The astrolabe is a very ancient astronomical computer for solving problems relating to time and the position of the Sun and stars in the sky. Several types of astrolabes 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. A typical old astrolabe 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. To use an astrolabe, you adjust the moveable components to a specific date and time. Once set, the entire sky, both visible and invisible, is represented on the face of the instrument. This allows a great many astronomical problems to be solved in a very visual way. Typical uses of the astrolabe include finding the time during the day or night, finding the time of a celestial event such as sunrise or sunset and as a handy reference of celestial positions. Astrolabes were also one of the basic astronomy education tools in the late Middle Ages. Old instruments were also used for astrological purposes. The typical astrolabe was not a navigational instrument although an instrument called the mariner's astrolabe was widely used. The mariner's astrolabe is simply a ring marked in degrees for measuring celestial altitudes.

Astrolabe.org

Rather than demo another new technology, Tom Wujec reaches back to one of our earliest but most ingenious devices -- the astrolabe. With thousands of uses, from telling time to mapping the night sky, this old tech reminds us that the ancient can be as brilliant as the brand-new.

TED Tom Wujec: Astrolabe

Amazing device and very beautiful, easy to use with astounding implications.



Never heard of it before to be honest. Here some historical facts:

An early astrolabe was invented in the Hellenistic world in 150 BC and is often attributed to Hipparchus.

Astrolabes continued in use in the Greek-speaking world throughout the Byzantine period.

Astrolabes were also used in the medieval Islamic world, chiefly as an aid to navigation and as a way of finding the qibla, the direction of Mecca.

Abū Ishāq Ibrāhīm al-Zarqālī (Arzachel) of Al-Andalus constructed the first universal astrolabe instrument which, unlike its predecessors, did not depend on the latitude of the observer, and could be used from anywhere on the Earth. This instrument became known in Europe as the "Saphaea". The astrolabe was introduced to other parts of Western Europe via Al-Andalus in the 11th century.

The first known metal astrolabe known in Western Europe was developed in the fifteenth century by Rabbi Abraham Zacuto in Lisbon. Metal astrolabes improved on the accuracy of their wooden precursors.

Link

Wanna build your own? Then have look at this pdf here


A timeless instrument.




[edit on 16-2-2010 by Clairaudience]

[edit on 16-2-2010 by Clairaudience]

ATS Thread:Lets do some Astro Charts!

I actually posted a thread re: a site that does this for you for purposes of astrology.

One of its uses.

[edit on 16-2-2010 by DaMod]

[edit on 16-2-2010 by DaMod]

reply to post by DaMod


Thank you, very interesting indeed.
I must say my astrology report is on the spot, good find!

The astrolab is a sophisticated piece of equipment. Kind of difficult to accept that civilizations that came before us were all primitive, yet in some ways we are being subliminally fed stories that refute the advancement of pre modern man. Take for instance, the flat earth myth that has been propogated in our era.

More here about astrolab and flat earth:


www.abovetopsecret.com...

reply to post by Alethea


Yes, I believe there were many sophisticated ancient civilizations, some we haven't found yet, many who's story vanished with time, and what remains is a blurry puzzle with loads of missing pieces. Yet the invention of the astrolabe clearly shows how well advanced some cultures were back then.

Don't put the flat earth theory to test, you may fall from the edge doing so

Different forms of the Astrolabe:

Large astrolabe

Ibn Yunus in the 10th century accurately observed more than 10,000 entries for the sun's position for many years using a large astrolabe with a diameter of nearly 1.4 meters.

Mechanical geared astrolabe

The first mechanical astrolabes with gears were invented in the Muslim world, and were perfected by Ibn Samh (c. 1020). One such device with eight gear-wheels was also constructed by Abū Rayhān al-Bīrūnī in 996. These can be considered as an ancestor of the mechanical clocks developed by later Muslim engineers.

Navigational astrolabe

The first navigational astrolabe was invented in the Islamic world during the Middle Ages, and employed the use of a polar projection system.

Orthographical astrolabe

Abu Rayhan al-Biruni invented and wrote the earliest treatise on the orthographical astrolabe in the 1000s.

Universal astrolabe (Saphaea)

The first astrolabe instruments were used to read the rise of the time of rise of the Sun and fixed stars. The first universal astrolabes were later constructed in the Islamic world and which, unlike their predecessors, did not depend on the latitude of the observer and could be used anywhere on the Earth. The basic idea for a latitude-independent astrolabe was conceived in the 9th century by Habash al-Hasib al-Marwazi in Baghdad and the topic was later discussed in the early 11th century by Al-Sijzi in Persia.

The first known universal astrolabe to be constructed was by Ali ibn Khalaf al-Shakkaz, an Arabic herbalist or apothecary in 11th century Al-Andalus. His instrument could solve problems of spherical astronomy for any geographic latitude, though in a somewhat more complicated fashion than the standard astrolabe. Another, more advanced and more famous, universal astrolabe was constructed by Abū Ishāq Ibrāhīm al-Zarqālī (Arzachel) soon after. His instrument became known in Europe as the "Saphaea". It was a universal lamina (plate) which "constituted a universal device representing a stereographic projection for the terrestrial equator and could be used to solve all the problems of spherical astronomy for any latitude."

Zuraqi

The Zuraqi is a unique astrolabe invented by Al-Sijzi for a heliocentric planetary model in which the Earth is moving rather than the sky.

Planisphere

In the early 11th century, Abū Rayhān al-Bīrūnī invented and wrote the first treatise on the planisphere, which was an early analog computer. The astrolabe was a predecessor of the modern planisphere.

Linear astrolabe

A famous work by Sharaf al-Dīn al-Tūsī is one in which he describes the linear astrolabe, sometimes called the "staff of al-Tusi", which he invented.

Astrolabic clock

Ibn al-Shatir invented the astrolabic clock in 14th century Syria.

Link

Ancient Islamic astronomy seemed very sophisticated for its time, driven by religious believes and the need to study the heavens.

Islam advised Muslims to find ways of using the stars. The Qur'an says: "And it is He who ordained the stars for you that you may be guided thereby in the darkness of the land and the sea."[10] On the basis of this advice Muslims began to develop better observational and navigational instruments, thus most navigational stars today have Arabic names.

Those were important times for astronomy and greatly influenced our modern perspective.

Another interesting video