Jantar Mantar is the one of the mathematical place in india. The word Jantra is derived from yantra, instrument, while the suffix Mantar is derived from mantrana meaning consult or calculate.The words jantar and ‘mantar (or yantra and mantra) means calculation instrument.

Jantar mantar also know as the equinoctial sundial.Because it consists gigantic triangular gnomon which having the hypotenuse parallel to the Earth‘s axis.There is a quadrant of a circle, parallel to the plane of the equator on the either side of the gnomon. So this is used to measure the time of the day.

In india there are 5 jantar mantar and from those largest one is Jaipur Jantar mantar.

History

In the 18th century, Maharaja Jai Singh II of Jaipur constructed five Jantar Mantars. In places like New Delhi, Jaipur, Ujjain, Mathura and Varanasi. They were completed between 1724 and 1735.

The jantars have evocative names like Samrat Yantra, Jai Prakash, Ram Yantra and Niyati Chakra; each of which are used to for various astronomical calculations. The primary purpose of was to compile astronomical tables, and to predict the times and movements of the sun, moon and planets.

Jantar Mantar, Jaipur

It name was inscribed on the UNESCO World Heritage Site. The construction was completed in 1734 CE.The features of this stone and brass instruments that were built using astronomy and instrument design principles of ancient Hindu Sanskrit texts. This monument operating in each of the three main classical celestial coordinate systems:

• the horizon-zenith local system
• the equatorial system
• the ecliptic system

To transfer from equatorial  to elliptical the Kapala Yantraprakara is used. The Kapala is an instrument which has been described in the suryasiddanta.

The monument was damaged in the 19th century. Restoration work was undertaken by the Major Arthur Garrett, a keen amateur astronomer, during his appointment he was the  Assistant State Engineer for the Jaipur District.

Construction:

Jantar mantar was built by local stone and marble. Each instrument having  an astronomical scale. It was marked on the inner lining of the marble. Bronze tablets, bricks and mortar were also used in building the instruments. Area of the monument is about 18,700 square metres. In 20 th century the original materials are used for the reconstruction of the monument.

Jantar Mantar is managed under the Archeological Sites and Monuments Act of Rajasthan since 1961, and protected as a National Monument of Rajasthan since 1968

(in jaipur)

Description of yantras:

• Chakra Yantra

four semicircular arcs on which a gnomon casts a shadow, thereby giving the declination of the Sun at four specified times of the day. This is equivalent of a wall of clocks registering local times in different parts of the world.

• Dakshin Bhitti Yantra

measures meridian, altitude and zenith distances of celestial bodies.

• Digamsha Yantra

a pillar in the middle of two concentric outer circles, used to measure azimuth of the sun, and to calculate the time of sunrise and sunset forecasts.

• Dhruva Darshak Pattika

observe and find the location of pole star with respect to other celestial bodies.

• Jai Prakash Yantra

two hemispherical bowl-based sundial with marked marble slabs that map inverted image of sky and allows the observer to move inside the instrument, measures altitudes, azimuths, hour angles and declinations.

• Kapali Yantra

measures coordinates of celestial bodies in azimuth and equatorial systems, any point in sky can be visually transformed from one coordinate system to another.

• Kranti Vritta Yantra

measures longitude and latitude of celestial bodies.

• Laghu Samrat Yantra

the smaller sundial at the monument, inclined at 27 degrees, to measure time, less accurate than Vrihat Samrat Yantra.

• Nadi Valaya Yantra

two sundials on different faces of the instrument, the two faces represent north and south hemispheres, the accuracy of the instrument in measuring the time is less than a minute.

• Rama Yantra

a double cylinder instrument that measures azimuth and altitudes of celestial bodies.

• Rashi Valaya Yantra

12 gnomon dials that measure ecliptic coordinates of stars, planets and all 12 constellation systems.

• Shastansh Yantra

next to Vrihat Samrat Yantra, this instrument is a 60 degree arc built in the meridian plane within a dark chamber. At noon, the sun’s pinhole image falls on a scale below enabling the observer to measure the zenith distance, declination, and the diameter of the Sun.

• Unnatasha Yantra

a metal ring divided into four segments by horizontal and vertical lines, with a hole in the middle; the position and orientation of the instrument allows measurement of the altitude of celestial bodies.

• Vrihat Samrat Yantra

world’s largest gnomon sundial, measures time in intervals of 2 seconds using shadow cast from the sunlight.

• Yantra Raj Yantra

a 2.43-metre bronze astrolabe, one of the largest in the world, used only once a year, calculates the Hindu calendar.

Jantar Mantar, New Delhi

The Jantar Mantar is located in the modern city of New Delhi. It consists of 13 architectural astronomy instruments. The construction was completed in 1724.

There are 3 instruments

• Samrat Yantra

  The Samrat Yantra also called as Supreme Instrument. It is a giant triangle that is basically an equal hour sundial. It is 70 feet high, 114 feet long at the base, and 10 feet thick. It has a 39 m hypotenuse that is parallel to the Earth’s axis and points toward the North Pole. On either side of the triangle is a quadrant with graduations indicating hours, minutes, and seconds. At the time of the Samrat Yantra’s construction, sundials already existed, but the Samrat Yantra turned the basic sundial into a precision tool for measuring declination and other related coordinates of various heavenly bodies.

• Jayaprakash Yantra

  The Jayaprakash consists of hollowed out hemispheres with markings on their concave surfaces. Crosswires were stretched between points on their rim. From inside the Ram, an observer could align the position of a star with various markings or a window’s edge.

• Misra Yantra

  The Misra Yantra was designed as a tool to determine the shortest and longest days of the year. It could also be used to indicate the exact moment of noon in various cities and locations regardless of their distance from Delhi.

The theories behind the instruments are found in texts by the 5th century CE Aryabhatta, 6th century CE Brahmagupta and Varahamihira, 9th century Lalla, 11th century Sripati and Bhaskara.

We all know Delhi is one of the most polluted city in the country but it doesn’t mean that species of green lush trees and bushes are extinct here. There are many splendid abundantly green gardens in this city. Here are few beautiful gardens of this beautiful city.

1. ‌GARDEN OF FIVE SENSES

The Garden of Five Senses covers a twenty-acre site. It is located at Said-Ul-Azaib village, close to the Mehrauli heritage area. The Garden of Five Senses is not just a park, it is a space with a variety of activities, inviting public interaction and exploration. The project developed by Delhi Tourism. The garden is sectioned into different areas, including a section on the lines of Mughal Gardens, pools of water lilies, bamboo courts, herb gardens, and solar energy Park. This garden is an alluring escape from the chaos of the city, the splendid lush greens of the garden and the majestic rocks around are well maintained.

‌2. DEER PARK

Deer Park is also known as A.N. Jha Deer Park and is located in South Delhi. Deer Park is named after famous Social worker Aditya Nath Jha. The park comprises many subsections such as Duck Park, Picnic Spots Rabbit Enclosures etc. The Park also contains many historical tombs of Mughal Era. The Park has four different wings i.e. Rose Garden, Deer Park, Fountain & District Park, Old Monuments and Hauz Khas Art Market.The park is accessible from Safdarjung Enclave and Green Park, Hauz Khas Village.

‌3. NEHRU PARK

Nehru Park was named after the first prime minister of India, Jawaharlal Nehru. Nehru Park, Delhi, is a large park covering 85 acres of area and is situated in the Chanakyapuri Diplomatic Enclave of New Delhi. It is nicely landscaped Park with lush green manicured lawns & small knolls in patches all across the area. The park has a variety of plants, many of which are aesthetically pleasing. These include Gulmohar, Pines, Ashoka, Palm, Neem, Champa & other such seasonal flowers. The park is one of the most famous places to visit in Delhi and a beautiful place to hang out during a sunny winter afternoon in Delhi. The best season to visit Nehru Park is October to March when the weather is at its best.

4. JAPANESE GARDEN

Swarn Jayanti Park, popular known as Japanese Park, is located in sector 11, Rohini. The park is abundantly green, clean walking paths and lakes with colorful boats. It is one of the most favorite picnic spot in Delhi. Japanese park is ideal to visit in the evening or early in the morning to enjoy the sunrise and enchanting setting. A must during spring is the flower festival organized in the park where you can spot hundreds of flower types that create a riot of colors and fill up the ambiance with their sweet fragrance.

5. LODHI GARDEN

The old Lady Willington Park is now known as Lodhi Gardens. It is a city park situated in New Delhi, India. It is spread over 90 acres. Lodhi garden houses the tombs of Sayyid and Lodhi rulers but it mainly contains Mohammed Shah’s Tomb, Tomb of Sikandar Lodi, Shisha Gumbad and Bara Gumbad. The gardens are situated between Khan Market and Safdarjung’s Tomb on Lodhi Road and is a hotspot for morning walks for the Delhiites.