In 1985 Dr. Vishnu ShridharWakankar – devoid of modern state- of- art equipment – located the exact spot at village Dongla 30km near Tehsil Mahidpur, District Ujjain, Madhya Pradesh where the Tropic of Cancer and the Local Longitude (which was the ancient Indian Time Meridian) intersect each other.

[Longitude 23° 26’ 42.91 “N]

[Latitude 75°45’ 43.31” E]

Height : 515m

It is at this spot, that on summer solstice on 21st June, the sun rays are perpendicular and do not cast any shadow at noon.

It may be noted that centuries ago Tropic of Cancer used to pass through Ujjain [23°11’] and that is probably the reason for the construction of ancient ‘Karka Rajeshwar’ temple at Ujjain.

Over the period due to Earth’s declination, the tropic of cancer has moved North and is currently passing through village Dongla in Mahidpur District of Madhya Pradesh.

Significance of Dongla in Time measurements

Currently the world follows Greenwich meridian (0°longitude) is the International Standard Meridian or Prime Meridian and the world timing is related to the time at Greenwich.

The question is, does Greenwich have any astronomical significance that would make it a choice of naming it as prime meridian? Post Christ the zero meridian was passing near the Louvre Museum in Paris. Did Paris also have any specific astronomical significance? Or was the naming of zero meridian a political decision based on the ascendency of British Empire.

Don Brown the author of “Da Vinci Code” says

“Long before the establishment of Greenwich as the prime meridian, the Zero longitude of the entire world has passed directly through Paris and through the Church of Saint Sulpice. The brass marker in Saint Sulpice was a memorial to the world’s first prime meridian, and although Greenwich has stripped Paris of the honour in 1888, the original Rose Line is still available today.”

Life on Earth and its day night schedule is based on the rays from Sun. We all know that rays of sun oscillate between the two tropics- Tropic of Cancer and Tropic of Capricorn. Both the tropics are the northern and southern extremes where sun rays can be parallel at noon during the respective solstice. Greenwich has no astronomical significance as it is neither on the tropics nor on the equator.

Dongla is significant in this sense, that it lies on the intersection of the Tropic of Cancer and local longitude which was our ancient Indian Time meridian and the sun rays are exactly perpendicular during summer solstice.


Dr Wakankar proposed that as Ujjain has been the seat of astronomical studies in ancient India and most of the Vedic calculations were based on the location of Tropic of Cancer at Ujjain, Dongla should now gain recognition as the world zero longitude point and international calculations of time should start from longitude [It should be DMT and not GMT]

Observatory (named after Dr. Vishnu Shridhar Wakankar)

A modern robotic observatory has been erected by Madhya Pradesh Council of Science & Technology at village Dongla near this spot.

The observatory dome is of 5 meters diameter and is installed at a height of 10 metres above the ground level. As the neighbouring area comprises of vast stretches of agricultural farms and no artificial lighting, this sites serves as an ideal spot for night observations.

Construction of the structure and dome has been done by M/s Pedvak of Hyderabad.

Dr. Tarun Bangia (ARIES Nainital), Mr. Bhupesh Saxena (MP CoST, Bhopal) and Dr. Padmakar Parihar ( IIA Bengaluru) have been responsible for the establishment of this observatory.

Telescope: 0.5 metre or 20” Planewave CDK Telescope. It is a corrected Dall-Kirkham Astrograph.

The f/6.8 telescope has an apparent focal length of 3454mm. The mounting is a German Equatorial from Paramount, and is capable of robotic control.

The CCD camera procured along with the CHEAP REPLICA WATCHES telescope is Apogee alta U9000, a large format, 38 x 38 mm square sensor with 3056 x 3056 pixels, which will result in a view of 38’ x 38’. The filed view is ideal for imaging medium and small galaxies. All the instruments have been supplied by M/s Audo Viso Pvt. Ltd.

This kind of observatory is also very important for outreach to all public, particularly children.

Reference : CLICK HERE

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