Most people in Karnataka are aware of the ancient astronomical observatories at Stonehenge in England, Newgrange in Ireland, Temple at Karnac in Egypt, Machu Picchu – Intihuatana Stone in Peru and the Jantar Mantar in Delhi but are oblivious to the astronomical wonder in the ancient cave temple of Gavi Gangadhareshwara atop a small hillock in Basavanagudi, Bangalore.

A celestial happening marks the Makara Sankranthi every year and the sun rays illuminating the South-facing idol inside the cave, indicates the shift of the Sun’s movement northwards (Dakshinayana to Uttarayana). In the evening, as the sun sets in the west, sun’s rays falling from the south-western part of the temple passes through an arch and a couple of windows placed perpendicular to each other and later through the horns of the Nandi(the bull mount of Lord Shiva) to fall on the idol of the temple for about 15 minutes(4.55 pm to 5.15 pm). It is as though the sun himself pays homage to Lord Shiva while welcoming Makara Sankranthi.

The phenomenon is a testimony to the fact that our ancient sculptors were extremely knowledgeable in the areas of astronomy and architecture. In the courtyard of the temple, there are mysterious monolithic stone structures – two large vertical discs on pillars, a large trident of Shiva, a small two-headed drum and two fans.

It is believed that such discs are not found in any other temple in Karnataka or south India. Their significance has been explained recently by scientists Dr.Jayanth Vyasanakere and Dr. B S Shyalaja of the Jawaharlal Nehru Planetarium, Bangalore, who have come to the conclusion that this temple has astronomical significance.

The study published in Current Science Journal opines that Suryapana and Chandrapana have been positioned for astronomical observations in the medieval period. The shadow of the bronze pillar (Dvajastamba) falls on the eastern disc for 40 minutes. The two discs have been installed in alignment to the summer solstice sunset and that explains the significance of the phenomenon on Makar Sankranti.

The discs stand parallel to each other a few metres apart. They have ornate sculptures of bulls appearing to support the weight of the discs and two perpendicular lines that intersect at the centre of the disc. “This kind of arrangement cannot be seen anywhere in the world. The arrangement is made specifically for astronomical purposes.” Dr. Shylaja explained.

Researchers believe that this apparatus was used to precisely mark the solstices and hence, measure time and their deductions which are based on marking the shadow of the western disc till the ‘last possible minute’ (which was around 40 minutes before the actual sunset) and then predicting the situation at the time of sunset.

The alignment of the arch, windows and Nandi to ensure that the sun’s rays fall on the idol on Jan 14th and the alignment of the two discs to summer solstice sunset is a fact that was unknown till now. The walls and windows have also been built in such a way that the light should reach the cave on Jan 14th.

Dr. S.K.Aruni of the Indian Council of Historical Research (ICHR) speculates that the cave was initially occupied by Jain monks by comparing the secluded location of the cave with similar ones in Sravanabelagola and Melkote. As per historical sources, this belief is supported by the dominance of Jainism in the region in the early part of the second millennium AD.

Later, it is believed that Kempegowda built the structures that are seen today in the early part of the 17th century, introducing the illumination event and making it a Shaivite temple.

The monolithic structures, the stone umbrella (Chatri) adjacent to the temple and a watch tower (Kavalu-Gopura) point to that fact. Legends shroud the presence of a dark tunnel going into the bowels of the hill.

Ardent devotees believe that there are actually two of these tunnels; one goes all the way to the north of India, to the City of Shiva, Varanasi, and the other to a temple town, Shivaganga, 50 km north-west of Bangalore. However this has not been proved but a tunnel exists on the banks of Kempegowda’s Kempambudhi tank, a few hundred metres away.

A high-walled prakara surrounds the cave temple considered a fine piece of Indian rock-cut architecture of the 9th century. In addition to a monolithic idol of Lord Shiva made of granite, the temple houses a rare idol of Agni, the fire god.

source: http://www.newindianexpress.com / The New Indian Express / Home> Cities> Bangalore / by Dr.Mamatha B R – Bangalore / April 11th, 2013