Jantar Mantar – A UNESCO World Heritage Site


11.15 hrs – The place started to get crowded as more and more tourists are venturing out to have a look at the City Palace. I headed towards yet another important structure in the heart of the city which is in contrast with the intricate carvings and the ornate pols or gates of the City Palace – The Jantar Mantar. The entry ticket costs Rs. 50/- for Indians! Grabbing my ticket, I walked towards this most impressive and fascinating astrological marvel, which is an expression of the astronomical skills and cosmological concepts of medieval India. In 2010, Jantar Mantar has been granted the UNESCO World Heritage Site Status.

Maharaja Sawai Jai Singh II who is fond of astronomy and used to study works of celebrated astronomers all over the world constructed a range of astronomical observatories throughout North India in between 1724 and 1730, called the ‘Jantar Mantars’. Out of the five Jantar Mantars in Delhi, Jaipur, Varanasi, Ujjain and Mathura (which no longer exists), the Jantar Mantar in Jaipur is the largest one. In fact, it is said that some of the instruments here in Jaipur are constructed by him and he constructed it so near to the City Palace so that he can make all the observations by his own!

The term ‘Jantar Mantar’ is derived from the Sanskrit terms ‘Yantra’ and ‘Mantra’ meaning ‘instruments’ and ‘formula’ respectively. I hired a guide here who knows a lot about the instruments present here. Jantar Mantar is a collection of 19 fixed architectural astronomical instruments that offer precise measurements of time, the azimuth, declination of the sun and the positions of constellations, along with several other astronomical phenomena.

I came across the Nadivalaya (the equatorial instrument), the Krantivritta (the ecliptic circle instrument) used to measure the longitude and latitudes of the celestial bodies, the Laghu Samrat Yantra (Small sundial), Shastana Yantra (sextant instrument) with which the variation in the sun’s diameter can be accurately measured and many more. But the centre of attraction here is the Vrihat Samrat Yantra (the ‘Supreme Instrument’ or Large Sundial), which is 90 ft high and measures time to an accuracy of two seconds is the world’s largest sundial.

My guide explained me about each and every instrument with perfect examples and I was awestruct when he explained me about calculating the time on Laghu Samrat Yantra and asked me to check the time he told on my watch and to my sheer surprise, it’s accurate! So far, I found Jantar Mantar as the most significant, comprehensive, and the best preserved of India’s historic observatories. And people who are interested in astronomy, here is your best bet if you want a scientific holiday 😉

VI NCERT Geo Gist – The Earth in the Solar System

  • The sun, the moon and all those objects shining in the night sky are called celestial bodies
  • The celestial bodies which have their own heat and light, which they emit in large amounts are called stars
  • Different groups of stars are called constellations. Ex: Ursa Major or Big Bear
  • One of the most easily recognizable constellation is the small bear or the Saptarishi, a part of the Ursa Major constellation
  • The North Star or the Pole Star indicates the north direction. It always remain in the same position in the sky
  • Some celestial bodies do not have their own heat and light. They are lit by the light of the stars. Such bodies are called Planets.
  • The word ‘Planet’ comes from the Greek word “Planetai” which means ‘wanderers’.

The Solar System:

The sun, eight planets, satellites and some other celestial bodies known as asteroids and meteoroids form the solar system.

  • The sun is about 150 million km away from the earth.


  • There are eight planets in our solar system. In order of their distance from the sun, they are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
  • Mercury is nearest to the sun. Takes only about 88 days to complete one revolution
  • Venus is considered as ‘Earth’s-twin’ because its size and shape are very much similar to that of the earth.
  • ‘Pluto’ may be called a ‘dwarf planet’.

The Earth:

  • The earth is the third nearest planet to the sun.
  • In size, it is the fifth largest planet.
  • It is slightly flattened at the poles. That is why, its shape is described as a Geoid.
  • The earth is a unique planet as it has life-supporting conditions like water, air and oxygen.
  • Earth is called a blue planet as its two-thirds surface is covered by water.

The Moon:

  • The earth has only one satellite, that is, the moon.
  • It’s diameter is only one-quarter that of the earth.
  • It is about 3,84,400 km away from the earth.
  • The moon moves around the earth in about 27 days. It takes exactly the same time to complete one spin.


  • A Satellite is a celestial body that moves around the planets in the same way as the planets move around the sun.
  • A Human-made Satellite is an artificial body. It is designed by scientists to gather information about the universe or for communication. Some of the Indian satellites in space are INSAT, IRS, EDUSAT etc.


Apart from the stars, planets and satellites, there are numerous tiny bodies which also move around the sun. These bodies are called asteroids. They are found between the orbits of Mars and Jupiter.


The small pieces of rocks which move around the sun are called meteoroids.


A galaxy is a huge system of billions of stars, and clouds of dust and gases. There are millions of such galaxies that make the Universe. Our solar system is a part of the Milky Way galaxy.