The Interpretation Centre, located on the premises of Jantar Mantar, Jaipur, was developed by the Amber Development and Management Authority.
The artefacts are displayed in two galleries, the audio-visual room and the Astrolabe Gallery. An audio-visual clip is played to introduce visitors to Jaipur's observatory, its yantras and their working principles. The centre also exhibits models of yantras such as the Kranti Vritta yantra, the Rama yantra, the Laghu Samrat yantra and the Nadivalaya yantra. The Astrolabe Gallery has astronomical instruments on display along with a telescope, logarithm tables and wax statues of Maharaja Sawai Jai Singh (1688–1743) having a discussion with Portuguese astronomers (Father Manuel de Figueredo and Pedro da Silva Letao) over astronomical literature and tables from Europe.
The astrolabe is an extremely versatile instrument, offering solutions to problems as diverse as telling the time during the day or at night, establishing the precise moment of a specific celestial event, constructing horoscopes, determining direction and measuring the height of buildings. At present, there are around 22 astrolabes in Jantar Mantar ranging from 110 mm to 500 mm in diameter. These astrolabes were constructed in Jaipur itself and are approximately 100–150 years old.
The Jantar Mantar complex also has a museum shop and a food-and-drinks kiosk.
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Interior view of the audio-visual room.
At the centre of this instrument is a wall constructed on the basis of the latitudinal position of Jaipur, with spherical quarters on either side. The shadow of the wall is cast on these quarters, through which Jaipur's local time can be ascertained during the day. Indian Standard Time (IST) can then be calculated by adding the difference in minutes to the local time.
This instrument is used to observe the position of the sun on the cusp, which is the imaginary line that separates a pair of consecutive signs in the zodiac or houses in a horoscope. It can also be used to determine the exact position of the planets and the stars in their respective zodiac signs through astrometry. This instrument is shaped like a globe resting on a pivot.
This includes a group of 12 yantras that represent the zodiac. For each sign of the zodiac there is a corresponding yantra. The equinox of the graduated fraction, which is marked on the cylindrical quarter as opposed to being at ground level, faces the yantra. This ensures that when the zodiac sign of the representative yantra approaches horizon level, its face coincides with the yantra at ground level. The Rasivalaya yantra is a set of unique instruments that were constructed exclusively in the observatory of Jaipur.
The Unnatamsha yantra consists of a graduated brass circle, 17.5 feet in diameter. A brass pointer fitted with sights and pivoted to the centre of the circle is used to make altitude observations. The whole brass circle is graduated into 360 sections and the circle can be revolved about its vertical diameter. It is fitted with an upright oblique line and, by placing a tube at its centre, altitude observations of the sun and other stars can be made with the help of astrometry.
These logarithm tables were first translated from French to Sanskrit by Pandit Kewal Ram, a scholar in Jai Singh’s court, and later by the scholar Govind Narayan Chaurasiya. In all three tables, the planetary motions are shown through trigonometric tables (chord of circle cosine and their degree, minutes and seconds). They are used for simplifying astronomical calculations.
This brass instrument is made of six circular parts, with the first five circles showing the movement of the sun, Venus, Mars, Jupiter and Saturn in their respective orbits. The signs of the zodiac are entered in the sixth circle, with their names in French, as per the Gregorian calendar. These are useful for determining planetary positions. According to the inscriptions on the astrolabe, the instrument was made by Francois Lemaire.
There are seven astrolabes in Jantar Mantar, sourced from different countries and inscribed in different languages. This astrolabe in particular consists of seven plates. Observations regarding the solar cusp as well as locating the positions of planets and stars can be done using this instrument.
This astrolabe shows the position of the planets, the names of the 12 zodiac signs from Aries to Pisces and the 27 nakshatras with descriptions of their positions in Arabic, Persian, and Sanskrit.
₹ 200 for foreign tourists
₹ 15 for Indian students
₹ 100 for foreign students
Entry for children below 7 years is free.