[Pramāṇa](https://indike.org/pramana/) › [Studies](https://indike.org/pramana/ins) › [Science, technology and education](https://indike.org/pramana/ins.science) › [The Astronomical Observatories of Jai Singh](https://indike.org/pramana/ins.science.kaye-1918) › c8.17 # The Astronomical Observatories of Jai Singh c8.17 The Astronomical Observatories of Jai Singh c8.17 - **Language:** English ### [c8.17](https://indike.org/pramana/ins.science.kaye-1918.c8.17) 23. The \*Unnatāṃsa Yantra\* is possibly another of Jai Singh's original instruments. It is a graduated brass circle, 17½ feet in diameter, suspended so as to revolve around a vertical axis. Jai Singh speaks of an instrument "\*Zāt-al-Ḥalqa\* (consisting of a ring) of brass, in diameter three gaz of the measure now in use" (see page 12); but the \*Zāt al-ḥalqa\* is ordinarily an armillary sphere. - [Previous: c8.16](https://indike.org/pramana/ins.science.kaye-1918.c8.16) - [Next: c8.18](https://indike.org/pramana/ins.science.kaye-1918.c8.18) - [Up: c8](https://indike.org/pramana/ins.science.kaye-1918.c8) --- Source: [https://indike.org/pramana/ins.science.kaye-1918.c8.17](https://indike.org/pramana/ins.science.kaye-1918.c8.17) · Pramāṇa