NEW DELHI: The relevance of the historic Jantar Mantar Observatory here will once again come to the fore as Nehru Planetarium in association with Park Hotel and the Archaeological Survey of India organises a public event in the Capital this Saturday -- which happens to be Equinox Day -- to check out the calibration markings on the grand old monument.
A panel of experts from the academic community will be present to give their advice on the future directions to be taken for restoration of the Jantar Mantar Observatory.
According to Nehru Planetarium Director N. Rathnasree, the Samrat Yantra at the Observatory has a unique history. Sadly, all the instruments built at this observatory have lain unused for most of the 300 years since the time they were built.
While the other instruments at the observatory need only some surface work and markings to be re-done on the instruments to make them work again, the Samrat Yantra has been considered unusable in its present condition in all the existing literature on the observatory.
The major change to its structure happened during the renovation of the Delhi Observatory in 1910, just prior to the coronation of King George III.
At that time, some portion of the excavated pit around the central gnomon of the instrument was filled up as the areas had become a swamp.
This resulted in the loss of a segment of the quadrant of the instrument on either side of the central gnomon. On account of these missing segments of the quadrants, all existing literature treats the Samrat Yantra as an instrument that is no longer usable.
Near the central gnomon of the Samrat Yantra, a horizontal cemented platform is present that seems to be a continuation of the quadrant.
This seems to indicate that the renovation work that resulted in the destruction of segments of the quadrant envisaged mixed usage of the original calibration of Jai Singh's astronomers on the intact segments of the Samrat Yantra and a calibration analogous to a horizontal European sun-dial on the horizontal platform where the quadrants are missing.
Such a calibration, if successful, would mean a revival of the Samrat Yantra for daily use as a sun-dial. This is what is being done by volunteers from the Nehru Planetarium, SPACE and the Amateur Astronomers Association.
Besides having the potential to be used as a wonderful teaching laboratory for positional astronomy, the observatories could also help the daily visitor easily understand and appreciate some simple astronomical observations.