Explanation: Jantar Mantar is an astronomical observatory located in Jaipur, Rajasthan, India. It was constructed by Maharaja Sawai Jai Singh II, a prominent Rajput ruler of the Kachwaha dynasty, in the early 18th century. The construction of Jantar Mantar began in 1728 and was completed in 1734. The observatory is a testament to the scientific and architectural achievements of the period and is recognized as a UNESCO World Heritage site.
Maharaja Sawai Jai Singh II was a keen astronomer and had a deep interest in the study of celestial bodies. He was also a patron of the arts and sciences, and his contributions to astronomy are well-documented. The observatory in Jaipur is one of five such observatories he built across India, including in Delhi, Ujjain, Mathura, and Varanasi. Each observatory was designed to serve as a center for astronomical research and education.
The Jaipur observatory, known as Jantar Mantar, consists of 19 architectural astronomical instruments. These instruments were designed to measure time, predict eclipses, and determine the positions of celestial bodies. The most famous of these instruments is the Samrat Yantra, a large sundial that can measure time to an accuracy of about two seconds. Other notable instruments include the Jai Prakash, which is used to determine the position of celestial bodies, and the Ram Yantra, which is used to measure the altitude and azimuth of celestial bodies.
The construction of Jantar Mantar was a significant achievement in the history of astronomy and architecture. The observatory not only served as a center for astronomical research but also as a symbol of the scientific and cultural achievements of the Kachwaha dynasty. The observatory continues to be a popular tourist attraction and a site of historical and scientific interest.
In conclusion, the correct answer is Maharaja Sawai Jai Singh II, who was responsible for the construction of Jantar Mantar in Jaipur during the early 18th century. His contributions to astronomy and architecture have left a lasting legacy in the history of Rajasthan and India.