| The maker and final destination of this flat astrolabe, which is in reasonably good condition, are both known. |
| On the back of the astrolabe, we use the alidade and the two pinholes to point a star. |
| He also wrote works on astronomical instruments, for example on constructing and using an astrolabe. |
| The construction of astronomical instruments such as the astrolabe was also a speciality of the Arabs. |
| The place of manufacture, which is incised together with the name of the craftsman on the back of the astrolabe, is given as Alcalá. |
| By far the most popular type is the planispheric astrolabe, on which the celestial sphere is projected onto the plane of the equator. |
