As if making monolithic rock-cut temples is not complex enough, ancient Indian architects and stone cutters outclassed themselves when making the Gavi Gangadhareshwara Temple in 9th century AD. Temple has been planned in a such a way that sunrays illuminate the shrine only for a short while in two periods of the year, including the time of the religious festivity Makar Sakranti.
Gavi Gangadhareshwara Temple originally was small temple cut out of monolithic rock circa 9th century. It is devoted to Lord Shiva and has typical attributes of Shaivite temples - including the Nandi ox in the front of the temple and the main shrine - Sivalinga - inside the temple.
More unique are some other sculptures. Depiction of Agni - god of fire - is one of the few in Southern India.
By far the most interesting feature of this temple though are two enormous rock-cut discs placed on the top of columns in the front yard of the temple. One disc is called Surya Pana (Sun disc) and the other - Chandra Pana (Moon disc), both have identical size with the diameter of some 2 m. Each of them rests on two smaller sculptures of Nandi bulls. Both discs have been produced in very high quality.
Discs are located parallel to each other. On both sides of the discs there are drawn orthogonal lines resembling crosshairs in the eye of telescope or marks of target.
There is not known any other temple in India with such discs. It is puzzling also that discs have crosshairs in each side. Discs are not aligned to cardinal positions of courtyard either - their location seems to be occasional. Initial purpose of these discs is not remembered by the locals.
Sunshine for the festival
Nowadays the temple is well known due to another unique peculiarity - every year in the afternoon of 14th January for some 20 minutes (from 4:55 to circa 5:15 PM) the Sun shines on Shivalinga.
This coincides with important local festival - Makar Sakranti - attracting thousands of people to Bangalore. This festivity marks the entry of the Sun into Capricorn - Makara - and is celebrated as harwest festivity.
Sunlight comes from the southwestern part of the temple, passes through an arch and two windows placed perpendicular to each other. Then the rays pass between the horns of the sculpture of Nandi bull and then illuminate the shrine.
Not all though know that the Sun shines on the shrine two times per year - from 13th to 16th Jaunary and from 26th November to 2nd December. In general the skies in this time of the year are clear.
Old paintings show different scene
Several old paintings, including two drawings of the British artists Thomas and William Daniell from 1792 show though somewhat different architecture and disposition of elements of this unique temple two centuries ago.
Paintings show that the area around the temple was barren and devoid of vegetation. Nowadays the view to the east is obscured by trees.
Temple has been supplemented by new walls and enclosures. This has been done with a great skill to change the earlier dates of the illumination to contemporary 14th January.
Later there has been added also a bronze pillar - Dhwajasthambha. Also this bronze pillar has unclear function - shadow of this pillar sometimes falls on the vertical mark on one of the discs. It is possible that Dhwajasthambha was installed to mark the entry of the Sun into Cancer.
Further analysis (1) of these old drawings shows that earlier the Sun illuminated the shrine during both the winter solstice and summer solstice.
Mysterious discs in the courtyard most likely were aligned to mark the summer solstice.