Astro-archaeology = archaeo-astronomy = Astroarchaeology = archaeoastronomy
Prasat Phu Phek
17°11.5296' N - 103°56.2356' E
|Above: Phu Phek Mountain in the left side of the picture. The picture was taken from a position straight true east of Phu Phek around summer solstice 2004. The sun is setting at its northernmost position and will set at the peak of Phu Phek at equinox.|
|Content of this web-page:
Prasat Phu Phek ('the temple
on the Venus Mountain') is located 22 km east - 'as the crows fly' - of
Sakon Nakon City and is the northernmost 'mountain-temple' in the
Ancient Khmer power-sphere. The term 'mountain-temple' is in this text
defined as a temple on a mountain-top. The term 'temple-mountain' is
in the literature as a temple constructed on an artificial
'mountain' or earth hillock, ''where the principal idol was placed on top
of a stepped pyramid'' (Briggs, p. 202). Both kind of temples share the same feature as
being elevated above the ground to a level where the horizon is visible,
which makes the site a well qualified place for astronomical observations.
With it's elevation of app. 520 m above sea level the temple is the
highest located prasat in the whole of the ancient Khmer Empire. At the
same time Prasat Phu Phek also indicates the northernmost extent of the
Khmer power sphere in the 11th century A.D.
|2. Dating Prasat Phu Phek
We have no written records as f. ex. engraved steles in Sanskrit or ancient Khmer about Prasat Phu Phek. An estimation of the age can only be done indirectly by comparing the style of art between this temples and similar temples, which contains written records.
The Fine Arts Department of
Thailand dates in the book, Ancient Sites in NE-Thailand, the site to
''probably belonging to the Baphuon art style'' (1050 - 1080 A.D. covering
the reigns of Udayadityavarman II and Harsavarman III).
One signpost on site gives the same dating. A second dates it to the 11th
- 12th century A.D. and thereby including Angkor Wat style. The latter
signpost continues: ''This is a Hindu sanctuary comprising of a large
east-facing sandstone tower and two small ponds in the north'' . . . ''As
no fragments of the superstructure were discovered, it is assumed that the
tower was incomplete. Two pieces of important objects were discovered
inside the sanctuary; namely, a stone base
with a square hole in the middle believed to have once held auspicious
items and the square base and octagonal middle part of a Siva Linga that
is usually topped with a cylindrical part, but broken of.''
The author of this paper believes that Prasat Phu Phek dates to Udayadityavarman II (Baphuon, 1050 - 1066) based on the 'pyramid shaped' base stones, which can also be seen at other definitely Baphuon style structures. The stone base or pedestal and the Siva lingam are widely found at other Baphuon to Angkor Wat temples.
Above: Eastern facade Prasat Phu Phek
Above: Prasat Phu Phek
Above: Plan of Prasat Phu Phek (courtesy to F.A.D.).
Above: Central chamber Above: Original setting.
|3. An old myth about Prasat Phu Phek
''A local ruler, Suwannapikka, who built the temple for veneration of Lord Buddha's ashes and Phra Mahakasapa, who was second to Lord Buddha, used to come to worship at Prasat Phu Phek together with 500 other monks. So the ruler decided to build two prasats! One on the top of the Phu Phek (phu = mountain, phek = Venus) Mountain and another, Prasat Naria Cheang Weng, on the plain. The first temple had a male work force and the second a female. The two groups should compete on the construction and the winner would host the ashes of the Lord Buddha. They were both told that the construction must be completed before Venus became visible at the horizon again. The female group faked Venus by the use of a balloon with fire hanging below in order to make the men believe it was Venus and when the men saw the fire-ball, they thought it was Venus and stopped working. And that is why the temple has been left unfinished until today.''
This is how the story was told to the author some years ago. Later on he became aware of that the story or myth is not that local. The French explorer Etienne Aymonier, who among other tasks, conducted survey on Khmer temples in SE-Asia in the last part of the 19th century, reports that he heard variations of the same story many places in Cambodia, Southern Laos and NE Thailand.
Notes on the myth:
|4. A new myth about
Prasat Phu Phek: Phu Phek as a 'solar calendar'
Phek around winter solstice 2002 the author noticed a hand-written sign in
front of the pedestal right outside the central sanctuary saying Surya
Phatthithin, 'solar calendar', and returning to Sakon Nakon at summer solstice
2004 the above mentioned Thai Tourism sign-board gave the same
information, which now apparently had been upgraded to official truth.
The report can not be regarded as a scholarly work as it contains no data which can be checked or verified. The conclusion is that Prasat Phu Phek is a 'solar calendar', Surya Phatthithin, with analogies to Stonehenge and Mayan temples. The calendar allegedly tells the days of solstice and equinox. One central argument is that the holes in the square pedestal (wrongly referred to as a yoni) are aligned with the equinoxes and solstices. One 'proof' hereof is that the pedestal should be oriented towards the equinoctial point (sunrise on equinox day). One picture shows a compass indicating that the orientation is 90 degrees magnetic east. Another 'proof' is a photo showing a person holding a plump in a plump line with the rising sun behind, and apparently taken some 10-15 minutes after sunrise on solstice day. A third 'proof' is photos showing the rising sun above the broken linga on equinox day, also some 10-15 minutes after sunrise. The technical arguments is the use of an astronomical computers programme, but there is no mention of data-in-put or data-out-put.
Comments on the photos:
Prasat Phu Phek can therefore not be regarded as a
'solar calendar' telling the equinox days and the solstice days. Especially
not the pedestal and the linga, which have been re-located from their original or
intended place. Neither of these two objects are parallel to one another,
nor are they oriented towards the equinoctial point, nor are they
The author believes that this was the intension of the constructor of Prasat Phu Phek (to visually depict Vedic New Year). But this does not make Prasat Phu Phek unique: Approximately 30% of all ancient Khmer temples, barays (water reservoirs) and ancient settlements are oriented true east.
|5. Determination of orientation
This chapter will demonstrate several methods used by the author when
determining the true orientation of a man-made construction.
5.1. Solar noon
The photos below show the shadow in
the eastern doorway of Prasat Phu Phek. It was calculated that solar noon
on equinox day, the 21st of March 2002, would be at 12:11:31. Photo no. 3
below (at 12:10:00) was taken the shadow apparently was aligned with the doorstep. The
difference between calculation and observation is 1:31 minute and
indicates that the doorway is either not oriented straight north-south or
that the top of the doorframe is leaning westwards.
Using compass there are two choices: A military compass or/and a map-compass. The first for long alignments the latter for short orientations.
|Compass readings at Prasat Phu Phek:
5.3. GPS measurements
5.4. Sunrise observations
6. The square pedestal as a calendric devise.
Azimuth of the rising sun at Phu Phek around winter solstice 2004:
The 21st of December: 114825'19''
The 22nd of December: 114825'21'' => difference from the day before = 0800'02'
The 23rd of December: 114824'52'' => difference from the day before = 0800'29''
The 24th of December: 114823'56'' => difference from the day before = 0800'56''
The 25th of December: 114822'25'' => difference from the day before = 0801'31''
The 26th of December: 114820.27'' => difference from the day before = 0801'52''
The 26th of December: 114817'59'' => difference from the day before = 0802'28''
The small differences in the azimuth of the rising sun from day to day around the solstices clearly demonstrates how difficult it is to determine solstice day by solar observations unless the alignments are 10 km or more. On an alignment as the pedestal it is impossible.
Final remark: As the solstitial angle changes with time - as demonstrated above - it also changes by latitude: A more northern latitude will have a larger solstitial angle, so if the square pedestal was moved to somewhere in southern China, then the solstitial angle would be identical to the 'half-diagonal angle' on 26.57° - and the pedestal (if enlarged) could serve as a 'solar calendar', but the facts are that these pedestals are only found within the extend of the ancient Khmer Empire.
|7. The equinoctial point
|The Ancient Khmer Empire, Lawrence Palmer Briggs, Philadelphia, 1951.|
|Ancient Sites in NE-Thailand. Fine Arts Department (F.A.D.). Bangkok.|
|Khmer Heritage In Thailand, with special emphasis on temples, inscriptions and etymology, Etienne Aymonier, Bangkok, 1999.|
12 October 2004