The Rashivalaya Yantra
The Rashivalaya Yantra is composed of 12 instruments, one for each of the zodiac signs. They are set at various angles in order to face the appropriate constellation. Based on the principle of the Samrat, which measures the latitude and longitude of a celestial object, a particular Rasivalaya instrument becomes operative when the first point of the sign of the zodiac it represents approaches the meridian. The Rashivalaya are used by astrologers to make accurate horoscopes (well, at least the celestial part of the horoscope is correct!). It is only found in the observatory in Jaipur.