How I discovered celestial geometry

Novelist and architect Srikumar M Menon writes about his research into how ancient architecture incorporated alignments to the sun

The narrow streets of Badami were dark, empty, and silent at 5 am. Streetlights with sodium-vapour lamps cast pools of yellow light at infrequent intervals. My footsteps were eerily loud as I trudged through the deserted streets, past remnants of imposing fort walls, the archaeological museum, and along the road which skirts the northern bank of Agastya Tirtha – the large, artificial tank to the east of Badami town. I was headed towards the Bhutnath group of temples, picturesquely sited on a platform that juts into the tank on its eastern side. The temple was a huddle of shadowy forms in the gloaming.

Since the temple complex would not open till 8 am, I passed it and crossed the small canal by its side, and picked my way through tumbled boulders and thorny bushes towards the base of the large sandstone massif which formed a ridge to the east of Bhutnath. It was tough going, even with the help of the light from my torch, and my clothes often snagged on the sharp thorns of the ubiquitous bushes.

At length, I found a clearing without bushes, and more importantly, with an unobstructed view of my target – a large sandstone boulder to the southeast of the Bhutnath Temple. I was in luck, for there was even a flat rock where I could comfortably stretch out. I sorted out my photographic equipment, and waited for the sun to rise.

But what was I, an architect by training, doing in this wild and wonderful setting, in the first place? Astronomy had been my first love, while growing up in my hometown of Cochin, and my passion for the night sky had simmered on the backburner during my architectural studies. I got a lucky break after graduating, when I was recruited as part of a team setting up an astronomical observatory in the Western Ghats near Pune.

After that stint, I tried my hand at architectural practice and soon realised that I did not enjoy it at all, and settled into a teaching job at Manipal University. It is in that beautiful university town that I got interested in the built heritage of the surrounding regions. Combining my newfound interests in ancient architecture with my old passion for astronomy, I did my doctoral studies examining megalithic monuments of India for deliberate astronomical alignments.

Two men hirsat Nilaskal, framing the setting sun on winter solstice

Back to the present 

The target of my attention – the sandstone boulder, was locally called Panchalinganaphadi. This massive boulder situated on the edge of the tank, with two small temples from the 10th century charmingly perched atop, constitutes one of the enduring images of Badami.

These are later constructions, however, in this capital city of the Early Chalukya dynasty, which boasts some of the earliest temples in stone in South India, dating from the 6th to 8th centuries CE. The main temple in the Bhutnath group is of Early Chalukyan vintage, though it has several later extensions and additions.

I was particularly curious about a small rock-cut feature at the base of Panchalinganaphadi, which I had noticed more than a decade ago. Amidst the surfeit of magnificent rock-cut as well as structural temples with exquisite sculptural embellishment that is Badami, this tiny excavation at the base of the rock had been given scant attention by the academic community, and one will not find mention of it in any book on Badami.

During my very first visit to Badami, I had asked one of the security guards at the site what this feature was. He replied that the rays of the rising sun light up this “cave” every day of the year. This piqued my curiosity – over subsequent visits to Badami, I measured the rock-cut “cave” and its orientation. It is a small excavation – barely 1.9 metres wide, and about a metre deep and a metre high. There are some unfinished caves of comparable size in Badami, but this cave was certainly not unfinished – its inside surfaces are all planed flat and there are pilasters and beams carved to define the edges. However, there is no deity enshrined within, or carved in relief on the rear wall – there is only an ochre circle painted on a white backdrop. Since this is a common sun symbol, the security guard’s story did seem credible.

I then created a CAD model of the cave and tested it for solar illumination. Care had to be taken to account for the massive ridge of sandstone which reared up in the east – the sun could illuminate the cave only after it cleared this ridge. My model confirmed the guard’s observation. The sun did illuminate the cave on every single day of the year, from its most northerly rising on summer solstice day to its extreme southerly rising on the winter solstice.

However, since this could arguably be mere coincidence, I did not read too much into the result. But when I happened upon an unfinished carving of the Sun God Surya on a boulder very close to Panchalinganaphadi, I was quite excited. There might be something in the solar connection, after all.

Vaishnava symbols, Chalukyan kings

The last piece of the puzzle fell in place when I considered the enigmatic image in a natural grotto near Panchalinganaphadi. In a natural cavern formed by a huge slab of sandstone which had collapsed against the rocky hillside, a seated figure carved on the rear wall had been variously interpreted by scholars as the Buddha or Mahavira. It did not make much sense because the figure was clothed, ruling out a Jina, and was too richly adorned to be the Buddha.

A rosary in the right hand of the figure too did not match with the iconography of the Buddha. Vaishnava symbols carved on the backrest of the throne on which he is seated added to the confusion. Only a description by the antiquarian Henry Cousens, where he insisted that the figure was a royal portrait of one of the Chalukyan kings, seemed to be credible enough. To the local inhabitants of Badami, the figure is known as “Koshtaraya,” or the leper king. According to oral legend, one of the Chalukyan kings had contracted leprosy and he used to live in this grotto and bathe in the Agastya Tirtha to cure himself.

Healing power of the sun

This proved to be the key to the puzzle – many temples to the sun were built as thanksgiving to the Sun God for curing leprosy – the most well-known of these being the Sun Temple at Konark. Krishna once cursed his son Samba for a perceived indiscretion of his, resulting in Samba getting afflicted with leprosy. It is believed that Samba would bathe in the Chandrabhaga River every day at dawn and worship Surya till he was cured of the disease.

A similar story concerns Mayura Bhatta, a 7th century poet who graced the court of Emperor Harsha. He is believed to have cured himself of leprosy after propitiating Surya by composing the Surya Shatakam – a poem in praise of the Sun God. The healing power of Surya for skin ailments, especially leprosy, was a well-known belief in ancient India.

Koshtaraya, and the unfinished image of Surya, along with the cave which received the rays of the rising sun everyday told a story of thanksgiving for an affliction cured by the healing orb in the sky.

Badami was a veritable laboratory of early temple-building activities where artisans from other parts of the Indian subcontinent mingled with local artisans to fashion several experimental constructions. It is to this spirit of experimentation which we can attribute the creation of a small but ingenious rock-cut alcove which faced the sun every day as it rose.

An aerial view of the Panchalinganaphadi boulder with the Bhutanatha temples in the background

Testing the theory

Computer models are very useful to assess the validity of such hypotheses, but nothing can beat actually witnessing such a phenomenon. That was how I found myself crouched on a block of sandstone on a rugged hillside, anticipating the sunrise on a pleasantly cool morning in March. It seemed to take forever for the sun to rise, but gradually the darkness began to lift and I could make out the monuments of the North Fort as they caught the light of the rising sun. A few early risers were going about their chores on the steps of Agastya Tirtha. A troop of bonnet macaques appeared, walking in single file over the lawns towards the Bhutnath Temple where they proceeded to sun themselves.

The golden glow of sunlight then lit up the tower of one of the temples atop Panchalinganaphadi. The glow crept slowly down its flanks, transforming the boulder to gold, as a troop of Hanuman langurs clambered all over the boulder, soaking in the sun’s warmth. I watched with bated breath – what if my calculations were wrong and the sunlight would not enter the cave? After what seemed like eternity, the first glimmer of sunlight shone on the rear wall of the cave, soon intensifying to illuminate the sun symbol strongly. After clicking several frames of the sun illuminating the cave, I shot the reverse view – from the cave, of the sun rising over the eastern ridge.

It was a heady feeling witnessing an inventive creation of a medieval artisan act out a celestial drama conceived more than a millennium ago. My head was buzzing as I left that amphitheatre of sky, light, and sandstone to the now-awake town where breakfast, and cups of hot tea awaited.

In search of megaliths

Megaliths are mostly funerary or commemorative monuments of prehistoric cultures, and several of them are impressive structures made of large blocks of stone. My work took me to megalithic sites literally from Kashmir to Kerala, as I examined them for undisputable alignments to celestial phenomena.

My perseverance finally paid off when I found a series of megalithic sites in southern coastal Karnataka which had intentional alignments to sunrise and sunset on the shortest and longest days of the year. One of these sites – Nilaskal, near Nagara, is an impressive arrangement of erect stone slabs, known as menhirs, over an extensive area. Arrangements of menhirs like these are called stone alignments.

My studies had suggested that pairs of menhirs at Nilaskal should frame the setting sun on summer solstice day, which is also the longest day of the year. The same menhirs would pair up with other menhirs to frame the sunset on winter solstice, when the day is shortest.

Armed with my prismatic compass and camera, I had visited Nilaskal on winter solstice day, and this was when I first tasted the high of experiencing a spectacle which our prehistoric ancestors from the Iron Age had arranged millennia ago.

Nilaskal was the climax of a series of smaller monuments, and the megalith-builders had learned well from the earlier monuments. Instead of a flat ground, they selected a site that sloped gently up towards the west, so that the western skyline is raised several degrees above the actual horizon. Thus, the haze that is generally present at the horizon is avoided and the setting sun framed by the menhirs of the alignment is spectacular.

The joy of rediscovering something our ancestors had conceived, and meticulously executed, and which was lost or forgotten in modern times, can be exhilarating. It is a thrilling business to peer into the minds of bygone generations and try to understand the knowledge systems they possessed, and the world views they had.

The artisan who carved the “sunlight cave” at Badami would have spent months observing the play of sunlight on the boulder, making markings on its surface, before deciding the exact spot to carve the alcove. Similarly, the megalith-builders of Nilaskal would have spent months, if not years, staking out spots on the sloping land with wooden poles for markers, before deciding the positioning, and layout of the menhirs, some of which are over 6 metres tall, and 3 metres wide. But what did these alignments to the sun mean to them? Though we probably will never know the answer to the question, it is likely it had something to do with the cult of the dead, possibly with a prehistoric belief in transmigration of the soul to the realm of the sun.

I have always believed in the need to communicate research findings to the public, and regularly publish illustrated articles about my research. The power of illustration by photographs cannot be overemphasised, given the stunning visual impact of most of these monuments and landscapes. I have published three books, the most recent of them being a collection of short fiction set in and around historical monuments and sites.

I have never regretted giving up active architectural practice for research in ancient architecture. I have been to some less-known sites in stupendous natural settings. I have surveyed Harappan monuments at Dholavira in Kachchh, searched for rock art in the mountains near Marayoor, Kerala and documented an exquisitely carved rock-cut temple in the Kumaon Himalayas. And at the end, when one takes stock, that is more than enough.

(Srikumar M Menon is a faculty member at the National Institute of Advanced Studies, Bengaluru.)

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