Sundial, calendar and Khmer temples
Astro-archaeology = Astroarchaeology
Prasat Preah Vihear
Archaeo-astronomy = archaeoastronomy
North 14.39038, East 104.68029

Introduction: The basic information needed to do calculations on astronomical events eventually related to an archaeological site is: Location, date of construction, and orientation. Also important is information about religious concepts and level of astronomical knowledge at the time of construction.
     We can measure the location and the orientation, but the time of construction is unknown. The temple was constructed some time in the 9th century, or maybe even centuries before. From stone inscriptions we have information about which gods were installed in the main sanctuary at various epochs, but very limited details about religious practices. No written information about astronomical knowledge at the time of construction has come down to us. From inscriptions we only know that various kings were praised for their Vedic knowledge, here among astronomy. As the ancient Khmers had close cultural ties to medieval India we can suppose that Indian astronomical textbooks as the Surya Siddhanta was in vogue in Kambuja in the end of the first millennium.
     The only 'hard evidence' we have is artistic expressions in stone. Like at so many other ancient Khmer temples the dikpalas (the Guardians of the Cardinal Directions) and the Kala figure ('time') are depicted on lintels and pediments above the doorways of the temple. A most interesting art-piece is a frieze depicting the Navagrahas (the Nine Planetary Deities), which expression and present location is not known to the author of this paper. We do not know how these religious expressions were perceived by the ancient Khmers. Neither do we have any written details about how and when, which rituals were performed. Hinduism and Buddhism originated in India but was probably practiced in 'Khmer way' in ancient Kambuja. The Khmer navagrahas originated in India, but were conceptually very different. Solar temples are absent, and so are mithunas (erotic art), which are very common at Shiva temples and Solar temples in India.

Location: North 14.39038, East 104.68029
Preah Vihear (Khao Phra Viharn in Thai) is located on top of the Dangrek Mountains, on the border between nowadays Cambodia and Thailand. The temple is located on Cambodian territory, but easily accessible from Sri Saket Province of Thailand. The associated baray (reservoir) right north of the sanctuary is located on Thai territory. The above position is measured at the main sanctuary.

Date: 9th century.
The construction of Preah Vihear went on continuously from the 9th to the 12th century. The first construction of Preah Vihear is credited Yasovarman I, who reigned
from 889 to 910, but ''a son of Jayavarman II (who reigned from 802 to 850) may have founded Preah Vihear even earlier when he took a fragment of rock from the Lingaparvata Mountain of Wat Phu in Laos to the site of Preah Vihear'' (ROVEDA, 2000:10). (Wat Phu = Vat Phou).
     No inscriptions inform about the year of construction. The first stone-construction was probably done in the last part of the 9th century, but the north-south orientated layout of the temple could well have been in use in older structures made by lighter materials.

Religion: Saivite (Bhadreśvara version)
Preah Vihear was a Hindu temple dedicated Shiva in his aspect of Shikharesvara (Lord of the Summit) and a Bhadresvara linga was installed in the main shrine.
     Prasat Banteay Srey, Prasat Sek Ta Tuy, Prasat Trapang Khyang from the 10th century were all dedicated to the linga Tribhuvanamaheśvara, which is the name of the god of Lingapura (Prasat Koh Ker). The three sanctuaries were made miśrabhoga (co-participant) of certain revenues with the god Bhadreśvara (BRIGGS, 1951:138). Bhadresvara, an angry version of Shiva, was also worshipped at Wat Phu, the cradle of Khmer culture which flourished in the beginning of the first millennium in what is now Southern Laos.

Right: Cambodian 100 riel note.


Orientation: 0.5 true bearing.
Two series of GPS-measurements (conducted by the author in 2004 and 2006) indicate that the orientation of the temple is not
100% straight north. Over a distance of 845 m the 'error' is approximately 8 to 9 m. Compass readings indicate that other parts of the structure (e.g.. Gopura IV) is approximately 1
from true cardinal orientation.
     Preah Vihear was constructed before the invention of the compass. Constructing an east-west oriented alignment
by use of the sun is relatively easy, but a north-south line (especially on sloping terrain) is a little more complicated.
     Preah Vihear has an axial layout resembling Prasat Vat Phou (Laos), Prasat Phnom Scisor (Cambodia), and Prasat Phanom Rung (Thailand).
     The stone floors at Preah Vihear have carved lines following the orientation of the structure. The lines run from door-step corner to door-step corner or mark the centre-line. Level IV has an intricate pattern of east-west and north-south lines.

Right: Carved east-west (91) centre-line in Gopura IV

Art related to astronomy:
A Navagraha frieze (the Nine Planetary Deities: Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Rahu and Ketu) was found in the forest near the temple (ROVEDA, 2000:24). If the reader knows where this frieze is exhibited today, the author will be very pleased to be informed, as he is collecting information on this feature, which has strong astronomical relevance.
     Dikpalas (Guardians of the Cardinal Directions) are depicted in the stone carvings of the temple: The Vedic head god Indra mounted on his vehicle, the elephant Airavata, fac
es east, the cardinal direction guarded by him. Yama on his buffalo guards the southern direction. Kubera guards the western direction and Brahma the northern.
     The Kala (literary 'time' and
in the literature also called 'the time-eating-demon') is represented in the centre of many lintels of the temple.

     Solstitial alignment are embedded in several parts of the layout. The 'solstitial angle' (my phrasing) is defined as the difference in azimuth angle of the rising sun at equinox and solstice.

Above: Deity on Kala

Right: Shiva Nataraja (the King of Dancers) on an elephant's head above the Kala. The depiction is atypical as the elephant is Indra's vehicle and the Dancing Shiva is normally not depicted on a vehicle. Shiva's vehicle is the bull, Nandin (see below).
     Shiva Nataraja is at Preah Vihear depicted on the pediment above the southern door of the mandapa ('entrance hall' in front of the main sanctuary
). Preah Vihear is as an exception oriented towards north. Most ancient Khmer temples are oriented towards the east, and within an angle that allows the rays of the rising sun annually to penetrate the entrance door of the temple and illuminate the main deity.
     Most temples also depict the leader of the
Guardians of the Cardinal Directions, Indra on his elephant, in the main orientation of the temple.
     The elephant could therefore symbolize Indra and together with Kala have a guarding function.



  Above: The western gallery surrounding the mandapa and the main shrine.
  Above: The mandapa is now used for Buddhist worship.
Above: North-south carved line in the floor.
Above: North-south carved line in the floor.
  Above: The western gallery.

  Above: One of the two giant nagas guarding the staircase before ascending to the Naga-platform.
Above: Gopura IV seen from south-east
  Above: View towards east.

Above: Preah Vihear seen from south-east. Two small towers can be seen in the right part of the picture.


Above: Stones for the construction were cut right south of the main sanctuary. View towards NW.

Above: Kala pediment on the eastern face of eastern 'library'
  Above: Northern entrance of Gopura III

Above: The dikpala guarding the southern cardinal direction: Yama on his blank buffalo above the southern door of Gopura III.


Above: The dikpala guarding the eastern cardinal direction: Indra on Airavata above the eastern door of the northern 'library'.

Above: Kala (literary meaning 'time').
  Above: Unidentified deity mounting Kala.
Above: The Churning of the Ocean of Milk. The devas and the asuras making soma.
  Above: The Sun and the Moon (in circles) carrying lotus flowers. Detail from the churning scene (see left).
Above: Ornaments.

  Above: Umamaheshvara: Shiva and his consort Uma on Nandin heading east like at Vat Phou.
Above: Krishna subduing the Naga Kaliya.
  Above: Close-up of Kristna.
Above: Ornaments on blind door.
  Above: E-W oriented sra (small reservoir) for ritual use.

Above: The eastern gallery and the view along the Dangrek Mountain chain.

  Above: The western gallery. The cannon behind the gallery is nor present anymore.
Above: Krishna subduing the Naga Kaliya.


BRIGGS, L. P. 1951
The Ancient Khmer Empire. American Philosophical Society (Philadelphia) vol. 41, 295 pp.. Reprinted by White Lotus Press, Bangkok, 1999.
FREEMAN, M. 1996 A Guide to Khmer Temples in Thailand and Laos. River Books, Bangkok, 1996.
HIGHAM, C. 2001 The Civilazation of Angkor, London 2001
JACQUES, C. and FREEMAN, M. 1999 Ancient Angkor, River Books Guides, Bangkok 1999.
ROVEDA, V. 2000 Preah Vihear, River Books Guides, Bangkok 2000.

Above: Bird-view of Prasat Preah Vihear (from a Cambodian 100 riel note).
  Above: Vishnu on Garuda on Kala  


12 August 2006 Asger Mollerup



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