The Jantar Mantar observatories have the potential to be used as a wonderful teaching laboratory for positional astronomy. The observatories could also function as a very aesthetic presence that allows the daily visitor to easily understand and appreciate some simple astronomical observations.
Their aesthetic presence is something that cannot be taken away, as long as the basic structures are intact (regardless of the state of their surface markings). However, their utility for the everyday visitor to bring basic astronomy alive cannot be achieved until all the markings on the instruments are restored correctly and there is a continuous presence of astronomy educators, students and amateur astronomers in the observatory. Most of the existing literature about the Jantar Mantar treats these as historical instruments that are presently not in a usable condition, on account of their state of disrepair. The existing literature also limits itself to giving a theoretical understanding of the possible usage of the instruments, but, there do not seem to be many observations taken by astronomers, using these instruments, that can actually characterise the properties and vagaries of each of these instruments.
Since 2004, this situation changed.
The first public usage of the Jantar Mantar Observatory of Delhi, for astronomical measurments, ever since the observatory fell into disuse late in the 18th century, was conducted by the Nehru Planetarium, New Delhi, on the 29th of March 2004, by helping all the visitors to the observatory on this day, measure the Altitude and Azimuth of the Sun and Venus and thereby measure the elongation of Venus on this day.
This was part of the educational activities conducted by the Nehru Planetarium, New Delhi, for the Transit of Venus activities.
Temporary calibrations for observations with the Jaiprakas Yantra
Students of Sanskriti school learning to use the Jaiprakas Yantra to measure the Altitude and Azimuth of the Sun
Following this, through 2005 - 2007, during many of the equinox and Solstice days, public awareness activities were conducted by the teams from the Nehru Planetarium, working together with the Amateur Astronomers Association, Delhi, and the Science Popularisation Association of Communicators and Educators (S.P.A.C.E.)
Amateur astronomers taking measurement of floor sectors of the Ram Yantra of the Delhi Observatory
This group of volunteers has been continously working with the Jantar Mantar instruments, generating awareness amongst the public and students about the usage of these instruments.
Nehru Planetarium, New Delhi, has been working intensely, since March 2004, towards the actual usage of the masonry astronomical instruments at the Jantar Mantar Observatory, Delhi, their calibration, and the preparation of templates for their restoration. The accuracies in Time, Alttude, Azimuth measurements achievable by students, even with the present state of disrepair, of the instruments, is amazing.
Planetarium, Amateur Astronomers Association, Delhi and S.P.A.C.E. conducted day long public awareness activities again on the 20th of March 2005, the equinox day. On this day, volunteers from these organisations were present at all the four instrument complexes - Misra Yantra, Samrat Yantra, Ram Yantra and the Jai Prakas, explaining their usage to the visitors. By Placing the necessary crosswires in one of the bowls of the Jai Prakas through temporary arrangements, volunteers marked the position of the Sun (the shadow of the crosswire) in the bowl all through the daylight hours on this Equinox day, so that the Celestial Equator was traced out in the bowl (temporarily, in chalk). This was one of the original markings on the bowl which is now erased. By placing a temporary rod over the central gnomon of the Misra Yantra, the Declination of the Sun was measured carefully on that day.
The Observers who participated in the awareness activities of 2005 and 2006 were - Dr. N. Rathnasree, Sneh Kesari, Vidur Prakash, Anurag Garg, Dayal Singh, Arpita Pandey, Ramesh Chikara, Vidushi Bhatia, Preetpal Kaur, Vikrant Narang, Ruchi Kaushik, Guntupalli Karunakar, Balchandran, Ajay Talwar, Naresh Kumar, O.P. Gupta, Chander Devgun, Chandrakant Misra, Anees Hassan Siddiqui, Varun Maheswari, Danish Contractor, Haran, Munish Lagad, Sahal Kaushik, Ramveer and Naveen Nanjundappa. In 2006, a small support in the form of a refreshment fund was provided to the volunteers on a monthly basis (for a period of six months), by the Apeejay Park Hotel, through the National Culture Fund, for carrying out these activities.
It saddens one to think that such unique astronomical heritage has been lying waste for most of the 300 years since the time of construction of the observatory. It is, however, encouraging that now, there are some regular astronomy teaching sessions being conducted on special days, at the observatory. However, a complete restoration of the markings on the instruments, detailed instructions for the visitors about the usage of the instruments, in an interpretation centre installed within the observatory, and the presence of a modern day clock accurate to a second, placed on a tall municipal building nearby, would allow visitors to measure and appreciate possible accuracies with these instruments.
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