Hi my name is William Greenwood, I am the Albukhary Foundation curator of the
Islamic world at the British Museum and welcome to my corner.
So part of my job is working on the new Albukhary Foundation galleries of the Islamic world
which will be opening in 2018 and one of the displays or redisplays, in fact
will be of our collection of Islamic scientific instruments, particularly those involved with reading the skies
so things to do with astronomy and things to do with astrology.
The best description or the best explanation for astronomy and astrology, the difference therein
is that astronomy is telescopes and astrology is horoscopes, so astronomy is actually looking at the sky
trying to understand celestial phenomena, stars, planets, so on and so forth
astrology is what those stars and planets and phenomena are supposed to do to us on earth.
Today astrology is seen as somewhat less scientific it's something see at the back of a newspaper generally
but for the very very very longest time from very earliest times up until really very recently
astrology was seen as, as much of, maybe even more of a science than astronomy.
Astronomy was there to serve astrology rather than the other way around.
There are a number of different objects that you can use to find out about the sky
and the most important one and the most long-lived one perhaps, is the astrolabe.
So, if you imagine it this is the universe in the palm of your hand
or at least the universe that you can see and comprehend.
This is you right here.
This is the horizon.
This is directly above you.
And this is out of sight because it's below the horizon.
Each of these pointers is for a particular star
and so, with this, you have a whole map of the heavens right in the palm of your hand.
It's used for all kinds of things, or it was used for all kinds of things, before the invention of workable clocks.
In the 10th century one astronomer worked out that
there were about a thousand applications for one of these.
Ranging from the religious, so you can find the prayer times or indeed the direction of Mecca
which is incumbent on Muslims for prayer. You could tell the times for, for example, crops to be planted
for taxes to be raised, rising and falling of tides, all kinds of things.
So this this is your basic instrument, as it were.
Let me go through this very very slowly, how does this work?
Well I think the first thing to do is to explain all the different parts of it
because each of them has very important aspect to it.
So to begin with this is the ring, this is the Halqa, which is connected to the
Kursi which in European terms is called the throne in English.
So why is there a ring on top? Well this is to hang it from so that you have it even
and you can hang it at eye level so it's always flat so this is always at eye level
it's not, it shouldn't be swinging about, if you hold it in your hand, you're not necessarily holding it flat.
This bit around the edge this is the Umm, this is the mother, the Mater in Latin
and this holds everything together and it has information so it has the zodiac on the outside
it has zodiacs, it has times, it has days, it has all kinds of information.
Inside there are plates and they're held inside the Umm, the mother.
So you can have sometimes up to about five, they're often engraved on both sides
So depending on how far north or south you are you'd use a different plate
so you'd have maybe one for Mecca, you'd have maybe one for Cairo, you'd have maybe one for Cordoba
and you can change them. On the front here this bit with the star pointers
this is known in Latin as the Rete, which is net, but in Arabic it's the Ankabut, which means the spider.
And this is your map of the stars each one of these points to a different star
and all of this is held in suspension by this, this is the pin, the Faras
and then finally on the back you have the Al-'idada, this is the ruler
this is what you use to sight with. Now you have to be quite the expert to know how it works exactly
but I can give you a generally good idea. So what you want to do first, if you want to tell the time
you need to use this. This is the Al-'idada you have to make sure that this is hanging straight
I won't hold it too much like that. And you would line this up with the Sun as such.
Imagine the Sun is over there somewhere. Obviously you wouldn't look through it to sight the Sun
because you'd go blind, everyone knows that's a bad idea, but you put your palm there
and you'd make sure that the Sun was shining directly through it
and then this would point you to a particular date, particular time
you'd actually use the zodiac to tell you what day or time it is
and then you would use the front and you would bring it to the same as that
and it will tell you all kinds of things, it'll tell you where stars are at that time
it'll tell you what you should be seeing in the sky
You can also do it in reverse. You can use a star if you know where it is on the pointer
and then you can line the Al-'idada up with that and it will tell you the same information but backwards
so that's a very very rough idea of how it works, I hope that makes some kind of sense.
Does it make sense? Makes sense to me anyway...
So please come and see these and various other magnificent items for reading the skies
in our new and upgraded Albukhary galleries of the Islamic world
which will be opening in autumn 2018. In the meantime, please subscribe for more
Curator's Corners and please watch the next film which should be just about here.