Sundial, calendar and Khmer temples
'The sun and 15 doorways of Phnom Rung'
Ninth 'Oxford' International Symposium
ninth “Oxford” International Symposium on Archaeoastronomy, held in
Peru in January 2011, a paper carrying the title 'The sun and 15
doorways of Phnom Rung' was presented for the audience.
By a mistake the paper carries my name as co-writer; but the content
does not express my opinions about Prasat Phanom Rung and was not
written in corporation with me!
My view on eventual archaeoastronomical significance of Prasat Phanom
Rung can be read in an
article published in 2007 in vol. 33.2 of the
Mueang Boran Journal.
The article was published four years ago and I have no
additional remarks, except that I have now completed a GPS-based
field-survey on orientation of some 300 Khmer temples in NE and
E-Thailand, which will be published later this year. The broad picture
is that nearly all temples are orientated allowing the rays of the
rising sun to enter the eastern gate of the temples. One half of the
temples are orientated towards true east (as for example
Prasat Sdok Kok Thom and the royal temples at Angkor); the other
half have orientations towards north-east (as for example
Prasat Phanom Rung). Only a few temples are orientated 5.5 degree
from true east. No temples are orientated towards the rising sun at
either of the solstices.
In the article in Mueang Boran
Journal I tentatively conclude that if the orientation of Prasat
Phanom Rung has archaeoastrological significance, then the astronomical
event is not merely solar; but solar-lunar: The time span from
the sunset aligned with the structure in March to the associated sunrise
in April equals one tropical lunar month. This can be evidenced by
observation: After having observed the sun set aligned with the 15
doorways of the temple then wait until the moon is visible and note the
moons location among the stars. The moon changes location every night in
a 27.3-days circle, called a tropical lunar month. When the moon
in April has returned to the position noted in March, then the sun will
rise aligned with the structure in April.
The time-span between the two associated solar-lunar
events is app. plus/minus14 days from equinox. And as there annually are
two equinoxes, then there are be two sets of solar-lunar events every
Seen by the eyes of a modern astronomer this is
beautiful; but we do not know, if it was intended and observed by the
ancient Hindu master-builders! If interpretation of inscriptions or
other evidences could confirm that the solar-lunar events were intended,
then Prasat Phanom Rung deserves a high rank among
international archaeological landmarks.
22 March 2011
© Asger Mollerup