And this one, this is a replica from a 15th century device.

So the North Star corresponds to the center of the device.

This is the mater, the scales on the back.

Step three is identify the star on the front of the device.

The bright stars correspond to little daggers on the rete.

So, the different parts of the astrolabe, in this particular type, the rete corresponds to the positions of the stars.

Astrolabes have an incredible history.

And it was a device that, in fact, is a model of the sky.

Probably not one made of brass. He would have one made out of wood, or paper. And the vast majority of this first computer was a portable device that you could keep in the back of your pocket.

You know, I've always wanted one of these.

This is one from Oxford.

It was the world's first popular computer.

This is an astrolabe. Pretty impressive, isn't it?

So, what does the astrolabe inspire?

If you were an educated child, you would know how to not only use the astrolabe, you would also know how to make an astrolabe.

And the astrolabes come in many different sizes and shapes and forms.

Astrolabes, like every technology, do evolve over time.

So, it's I think astrolabes are just remarkable devices.

And that is because we live in a galaxy which has a flattened, disk like structure.

And in the back you can see a spider web pattern.

For my thesis I actually built one of these out of paper.

And the mater has some scales and puts it all together.

Tom Wujec demos the 13th century astrolabe

And the central idea that makes this computer work is this thing called stereographic projection.

Now, the real genius of the astrolabe is not just the projection.

So, an astrolabe is relatively unknown in today's world.

And you can see the different components.

And it would take a full university course to illustrate it.

So, would little Lewis have an astrolabe?

But, at the time, in the 13th century, it was the gadget of the day.

It can be used for calculating mathematical equations of all different types.

And so, this astrolabe is on loan from us from the Oxford School of Museum of History.

First thing that you do is you select a star in the night sky, if you're telling time at night.

But let me show you how to work this device.

as you glance at your iPod to just check out the time.

And I think what is common to all astrolabes is that they are beautiful works of art.

In June 1994, two scientists using the HST discovered disks of protoplanetary dust around stars in the Orion Nebula region of the Milky Way galaxy.

There is a quality of craftsmanship and precision that is just astonishing and remarkable.

On the back there is scales and measurements for terrestrial navigation.

The newly found disks contain many of the same basic chemicals that compose the planets in our solar system.

So, that's just one use. Incredible, there is probably 350, 400 uses.

Well, the way you would do it is by using a device that's called an astrolabe.

And in this book, little Lewis would know the big idea.

So, step two, I hold the device up, and then I sight its altitude there so I can see it clearly now.

Already, the tracking system has been used to demonstrate satellite broadcast of compact disk (CD) quality radio to conduct measurements of path diversity for commercial mobile satellite communications.