It wasn't just
textual material that was translated and circulated,
but scientific instruments too.
The astrolabe is one of the most complex of these machines
and these instruments and also one of the most exciting to consider.
So what is an astrolabe?
The astrolabe is a hand-held circular machine,
often made of brass, but also silver and copper
that provides a stereographical perspective of the cosmos.
It allows one to read the skies for the purposes of timekeeping,
to chart the movement of the sun, the moon, planets and the stars,
and to compute natal horoscopes.
And these are just a handful of its uses.
As an object
the astrolabe is a circular disk that contains several
movable parts with a ring handle attached to the top.
We can see that from the images on the screen.
The front of the astrolabe, called the mother, is engraved with various
gradient markers on the inside and 24 symbols around the edge,
marking out 24 hours of the day. On top of the mother
sits a movable cut out plate called a rete, a celestial map
that marks out the ecliptic with the zodiac and the fixed stars,
and a moveable pointer that sits on top of the rete called an alidade.
The instrument, as we can see on the screen,
also comes with a removable and portable plates
that are specialized to the latitude of the area.
And these plates are then placed inside the mother.
The back of the astrolabe can also be used,
and it contains various calendars and markers for time and degrees
that can be used to chart the movement of the sun.
And in the astrolabe, we find two parts
the rete at which contains the star map, which is the celestial part,
then the movable plates that give the latitude of the area
in which the astrolabe is used is the terrestrial part.
The terrestrial part.
Now, in addition to the precise, intricate engravings
needed for astronomical calculations, for marking out
the degrees of time and scale, which included using scripts,
Arabic, Latin, Hebrew, depending on where it was produced,
sometimes containing more than one of these languages.
The Astrolabes could also be highly decorated
with human and animal figures and vegetable motifs, demonstrating
the type of intricate work required by artisans and craftspeople
who were involved in their production.
Now, the
astrolabe was first conceptualized and created in classical Greece.
The name itself means star catcher in Greek.
Knowledge of the astrolabe was then taken up by scholars writing in
Arabic, developing both in terms of the astronomical mathematics
needed to use and understand the machine
as well as its intricate design and esthetics.
We get a little sense of the history of the astrolabe
in Ibn al Nadim's encyclopedic catalog.
Ibn al-Nadim composed, his catalog known as the Fihrist,
or the index in the late 10th century in Baghdad
and he provides us with a brief history of the scientific instrument.
He tells us in ancient times the astrolabes were plain.
The first person to make them was Ptolemy,
the first Muslim, he tells us, to make a plain astrolabe was Abiyyun
al-Batriq.
Then the instruments came to be made in the city of Harran.
Later, they were distributed, becoming
common and increasing in number,
so the work became plentiful for the makers during the Abbasid period,
from the days of Al-Ma'mun to this, our own time.
Now, the physical astrolabe instrument
was also usually accompanied by technical handbooks known as the art
and the use of the astrolabe Kitab san'at
al-asturlabat wa'l-amal bi ha.
The earliest of these was composed by the mathematician Muḥammad
Ibn Mūsā Al-Jwarizmī who worked in Abbasid, Baghdad,
and whose handbook and astronomical mathematical tables
were known in al-Andalus by the mid 10th century.
Indeed, it's from al-Andalus that knowledge about the astrolabe,
both the physical instrument and the technical handbooks
spread to Latin West and into Northern Europe,
first reaching Catalonia, which was under French domain
where we find the earliest Latin astrolabe. From here
knowledge about Astrolabes and Astrolabes
themselves was circulated and created across
different spaces in Northern Europe and Western Europe.
And in a Christian context
the astrolabe was adapted to thinking about feast days,
determining times and the days of feast days,
whereas in an Islamic context and Astrolabe was used to determine
the times of prayer.
Now to think a little bit
more about the transmission and movement of astrolabe.
I want us to turn to textual material in particular and to England.
In 1150, the Englishman Adelard of Bath writes
a treatise on an astrolabe in Latin, and he dedicates this to a young
Henry Plantagenet,
the future King Henry II.
Adelard directs this didactic manual to Henry.
He calls him a relative of the king
who has reached an age of intellectual maturity and is now,
and I quote, willing to study the teachings of the Arabs
concerning the sphere of the universe
and the orbit and movement of the stars.
Here he directs the young Henry to the teachings of the Arabs,
noting, and I quote, I shall write down in Latin what I learned
from the Arabs about the world and how to understand it.
It is from Arabic learning that
Adelard of Bath derives his understanding of the astrolabe,
and it's this that he wants to pass on to young King Henry II.
Two centuries later, in 1391, the English poet Geoffrey Chaucer
write his treatise on an astrolabe, the first treatise to be written
in English. Written for his 12 year old son, Louis.
He also provides an introduction to the treaties.
Well, he gives us a little sense of the history of the astrolabe.
A text, an instrument that has
an instrument that has been known
in various different language traditions, including the Arabs,
where he tells us the teachings of the Arabs is
he tells us the astrolabe is part of the teachings of the Arabs.
And the phrase that he uses, known to us by the Arabians in Arabic.
And here we see with Chaucer's treatise on the Astrolabe
another linguistic shift where we move from Greek,
from Greek into Arabic, into Latin, and now into English,
where English then become becomes a newly emerging
language of science, deeply connected to Arabic learning.