I have come to Delhi with Jagrata & Judhajit for a couple of days for some personal work in New Delhi. We are staying at hotel The Park in New Delhi. It’s just opposite to the iconic architectural masterpiece of 18^th century – Jantar Mantar.

Jagrata and I were remembering this place as she used to wait with Judhajit in the lawns of Jantar Mantar for me to come from my office in the evening and pick them up for shopping etc in Connaught Place area. Babai was toddler then. 🙂

Judhajit and I walked across from our hotel to the Jantar Mantar. It is an equinoctial sundial, consisting of a gigantic triangular gnomon with the hypotenuse parallel to the Earth’s axis. On either side of the gnomon is a quadrant of a circle, parallel to the plane of the equator. The instrument is intended to measure the time of day, correct to half a second and declination of the Sun and the other heavenly bodies.

The jantars have evocative names like, Samrat Yantra, Jai Prakash Yantra, and Mishra Yantra; each of which are used to for various astronomical calculations. The primary purpose of the observatory was to compile astronomical tables, and to predict the times and movements of the sun, the moon and planets. Designed for the observation of astronomical positions with the naked eye, they embody several architectural and instrumental innovations. This is the most significant, most comprehensive, and the best preserved of India’s historic observatories.

It is an expression of the astronomical skills and cosmological concepts of the court of a scholarly prince at the end of the Mughal period. The site is one of five built by Maharaja Jai Singh II of Jaipur as he was given by Mughal emperor Muhammad Shah the task of revising the calendar and astronomical tables. The construction was completed in 1724.

The primary purpose of the observatory was to compile astronomical tables, and to predict the times and movements of the sun, moon and planets. Some of these purposes nowadays would be classified as astronomy. Maharaja Jai Singh II built five similar observatories in west-central India, all known by the name Jantar Mantar. They are located at Jaipur, Ujjain, Mathura and Varanasi.

While the purpose of the Jantar Mantars is astronomy and astrology, they are also a major tourist attraction and a significant monument of the history of astronomy. The sundial at the Jaipur Jantar Mantar is the largest stone sundial in the world. The Jaipur Jantar Mantar is a UNESCO World Heritage site.