| Another special type of telescopic instrument is the modern version of the astrolabe. |
| He is famed as the first person to write a Sanskrit treatise on the astrolabe. |
| When the ten minutes are up, as signified by the ding of an egg timer, a piece of nautical equipment as pedigreed as an astrolabe or a sextant. |
| 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. |
| By far the most popular type is the planispheric astrolabe, on which the celestial sphere is projected onto the plane of the equator. |
