Jaipur, Nov. 18 The 17th century world famous Jantar Mantar in Jaipur is undergoing a 4.5 million-rupee refurbishment job.

The historic monument is a collection of architectural astronomical instruments, built by Maharaja Jai Singh II.

At 27 metres, an instrument known as the Samrat Yantra is the world's largest sundial.

The renovation is being carried out for the second time after the first one carried out in 1901.

"The sun sign instrument was last renovated in 1901. This is the second time, the restoration work is being carried out. The mixture for construction work is prepared in the same traditional way maintaining the precision and the accuracy," said Pandit O P Sharma, Superintendent of Jantar Mantar.

The renovation is carried out very precisely taking care of the ingredients, which were used 108 years ago.

"The renovation is carried out similar to that of the traditional way where lime and tiny rocks are used as a mixture for construction purposes. Accuracy of instruments is also being taken care of," Sharma said.

The 4.5 million-rupee renovation project is getting public appreciation as well.

"This is very good. It is very important heritage building. It should be fully renovated, so that our future generation will also be able to see it," said Ramesh, a visitor.

"Because we have come from the United States and there is nothing like this to visit there. These monument are different, unusual," said Seema from the U.S.

The observatory consists of 14 major geometric devices for measuring time, predicting eclipses, tracking stars' location, ascertaining the declinations of planets, and determining the celestial altitudes.

Each is a fixed and 'focused' tool.

Built from local stone and marble, each instrument carries an astronomical scale, generally marked on the marble inner lining.

The Jantar Mantar was declared a national monument in 1948. By: Lokendra Singh (ANI)