On the 6th of April 2003 the sun went down to the left (south) of the lingam, confirming the writers assumption from previous observations that the alignment of the temple is 84.5 degrees from true north (not magnetic north).
 

    
     On the 7th the horizon was cloudy and it seemed like that the sun would not be visible. A few minutes before sunset the sun became visible and everybody were excited, as the picture to the right indicates.
     The first public show was a success.

Fig. 7: Sunset 7 March 2003

Fig. 9 and 10: Based on the solar event in March 2003 the author was invited to preside at the annual festival in April, when he took no photos due to the many visitors attending the event. The photos above are from the Thai TV Channel 5.

     As a free-lance adviser to the director of Prasat Phanom Rung Historical Park the author proposed the annual festival in 2004 to start on Friday the 2nd of April, which happens to be the birthday of the protector of the temple, Crown Princess Sirinthorn.
     The sunrise was calculated to be visible through all 15 gates on the 2nd, on the 3rd straight, and on the 4th visible too (see fig. 12 above). The festival was scheduled to to coincide with the above dates, but unfortunately the horizon was obscured by clouds and many visitors were disappointed.

     Being now aware of that there actually are 2 solar events in spring 2004 (figs. 11 and 12) the governor of Buriram declared the period for 'The Sacred Month of Prasat Phanom Rung'. A Brahmin ritual was preformed at the solar event in March.
     The 'Sacred Month' was a surprise for the author, who merely visits Prasat Phanom Rung to use it's 15 doorways as an astronomical devise (a dioptra) to check various astronomical computer programmes and his GPS-devise.

The two solar events at Prasat Phanom Rung in autumn 2004 (2547 B.E.)

     The sunrises in September were obscured by clouds and no photos were taken. September is in the end of the rainy season.

     In October the weather was better, but only on the 4th and 5th (figs. 13, 14, 15, and 16). The sunsets were calculated to be visible on the 5th, 6th and 7th, which was confirmed by the sunset the 5th (fig. 16).

Fig. 13: Sunset the 4th of October The sun was only visible through 11 gates		Fig. 14: Sunset the 5th of October Observed from behind Nandin, the vehicle of Indra
Fig. 15: Sunset the 5th of October Observed from behind the Nandin		Fig. 16: Sunset the 5th of October Visible through all 15 gates

A: The sunset in March: The sun will set straight on Tuesday the 7th. (see figs 17 and 18)
NB: The Tourism Authority of Thailand (T.A.T.) and Phanom Rung Historical Park also informed the 7th.
The event was not observable due to clouds.

Fig. 17: Local horizon gives the option of observing  the sun aligned the 6th - setting in the Yoni (pedestal).		Fig. 18: Calculated and geometrically depicted (CAD-CAM) paths of the setting sun.

NB: Prasat Phanom Rung is located on a small mountain with a local western horizon within the range of 0.5  - 1.0° below mathematical horizon (sea-level). The local horizon towards east is supposed to be in the range of 1.0  - 1.5°. The grid used on the graphics is 0.5°. Local horizon must be taken into consideration when calculating time of visibility of the sun.

Fig. 21: ASTRONOM calculation: Sunrise on 3 March at 06:0338
Fig. 22: The sunrise in April: Monday the 3rd.           The added perspective lines (red, fig. 22) meet in the perspective point, which marks the orientation of the door-ways of Prasat Phanom Rung. Point of observation: Lower left corner of the western doorway. The yellow line marks the path of the rising sun if it rose from the perspective point. The yellow line passes straight through the sun indicating that the perspective point is identical to the orientation of the temple. Conclusion: The sun rose straight on the 3rd of April 2006 - not the 4th, as officially announced (T.A.T.). (See Appendix II: Perspective Drawing as an Analytic Tool).

C. The sunrise September 9 (14 days before autumnal equinox)      The sun was calculated to be 50% visible at mathematical horizon at 05:57:57 and aligned with the structure of the temple at 06:02:27.      The 9th and 10th clouds obscured the view of the rising sun. The photo to the right was taken the 8th.      The corners of the door-ways are unfortunately  not distinguishable so the picture cannot be used for perspective drawing (see Appendix II).      The photo was taken at the moment when the sun was calculated to be at the mathematical horizon confirming that the local horizon is lower than the mathematical (clouds are visible below the sun). D. The sunset October 7 (14 days after autumnal equinox)      The sun will be aligned with the centre-line of the doorways at 17:53:52 and be located just below mathematical horizon (sea level): If observed at the nearby Prasat Muang Tam or at the ocean the sun would be below the horizon - but at Phanom Rung it will still be visible. The reason is that the temple is located on a small mountain with a local horizon below mathematical horizon.      An observer sitting down in front of the eastern door-way will have good photo opportunity on the 6th.      See calculations below.

Fig. 23: Sunrise 8 September at 05.58

 

Fig. 24: The paths of the setting sun on various days in October 2006. Point of observation: On the centre line with the camera at the level of the doorstep. A sitting person will have the best photo opportunity on October 6.		Fig. 25: The paths of the setting sun on various days in October 2006. Point of observation: On the centre line with the camera at the level of mid door-way. A standing person will have the best photo opportunity on October 7.

The 4 solar events at Prasat Phanom Rung in 2007 A.D. (2550 B.E.)

     The annual Light and Sound Festival is set to run from the 3rd to the 5th of April and the Tourism Authority of Thailand informs (in Thai only) that the sun will be visible straight through the 15 door-ways all 3 mornings at 06.00.
     The provincial office of Buriram province also announces the event - and also only in Thai: รับพลังแห่งแสงอาทิตย์แรก ผ่าน 15 ช่องประตูปราสาทพนมรุ้ง
 

Fig. 26: The paths of the rising sun on various days in April 2007. Point of observation: On the centre line with the camera at the level of the doorstep. A sitting person will have the best photo opportunity on April 4.		Fig. 27: The paths of the rising sun on various days in April 2007. Point of observation: On the centre line with the camera at the level of mid door-way. A standing person will have the best photo opportunity on April 3.

     The solar events in September and October 2007 are officially announced to happen on the 8-9-10th of September and the 5-6-7th of October (Source: Sign-board exhibited at Prasat Phanom Rung in April 2007 and brochure made by Buriram Provincial Office, Tourism Authority of Thailand and the Fine Arts Department).
     These dates are unfortunately wrong!
     The correct date are 9-10-11th of September and 6-7-8 October. The dates when the sun will be aligned with the 15 door-ways of Prasat Phanom Rung are Monday the 10th and Sunday the 7th of October.
 

Fig. 28: The paths of the setting sun on various days in September 2007. Point of observation: On the centre line with the camera at the level of mid door-way, 7 m outside the eastern door.		Fig. 29: The paths of the rising sun on various days in October 2007. Point of observation: On the centre line with the camera at the level of mid door-way, 7 m outside the eastern door.

All Astronomical events in 2007 related to Prasat Phanom Rung:
 

Month	Day	Time	Event	Comments
March	04	06:20:56	Total lunar eclipse	Starts at 04:30:00
March	07	18:13:55	Sunset in 15 doors	Aligned with the structure. Moon in Citra
March	21	07:07:25	Equinox	Vernal
March	19	08:24:00	Partial solar eclipse	Starts at 07:50:55. Max. eclipsed surface: 7.0%
April	04	06:07:54	Sunrise in 15 doors	Aligned with the structure. Moon in Citra
August	28	18:22:19	Total lunar eclipse	Moon rises eclipsed at sunset
September	10	05:57:47	Sunrise in 15 doors	Aligned with the structure. Moon in Magha
September	11	17:31:21	Partial solar eclipse	Not visible in Thailand
September	23	16:51:13	Equinox	Autumnal
October	07	17:52:29	Sunset in 15 doors	Aligned with the structure. Moon in Magha

     The astronomical events related to the 15 door-ways of Prasat Phanom Rung is more than merely sunrises and sunsets. See the article - Celestial Ronp! - which was published in HORIZONS, Bangkok Post, 1 March, 2007.

     A longer and more detailed article on the 3 astronomical aspects of Prasat Phanom Rung will be printed in the April-May issue of the Muang Boran Magazine, titled The Sun, the Moon and Rahu at Prasat Phanom Rung - Notes on archaeo-astronomy.
The article will be printed in Thai as well: สุริยัน จันทรา และราหูที่ปราสาทพนมรุ้ง : ข้อสังเกตทางโบราณดาราศาสตร์

     Muang Boran Magazine brought in 2004 an article, บันทึกดวงอาทิตย์ที่พนมรุ้ง: Unseen in Thailand, where the former director of Phanom Rung Historical Park, Miss Nongkhran Suksom describes the solar-lunar aspects of the 15 door-ways of Prasat Phanom Rung.

The 4 solar events at Prasat Phanom Rung in 2008 A.D. (2551 B.E.): ENGLISH / THAI
 

¤

I: EQUINOX 2006-2010
II: PERSPECTIVE DRAWING AS AN ANALYTIC TOOL
III: POPULISTIC ARCHAEOASTRONOMY
IV: PHANOM RUNG IN THAI ENCYCLOPAEDIA
 

     Based on own observations of sunsets and sunrises through the door-ways of Prasat Phanom Rung the orientation has been determined to be  84.5°. The difference from 90.0° east (the equinoctial point) is 5.5° - or in days: approximately 14 days from the equinox days.
     The calculation of the solar events at Prasat Phanom Rung is therefore rather simple: Determine the equinox days and add/subtract 14 days.

     It must be emphasised that this simple calculation is 'a rule of thumb' and must be followed by more exact calculations for the year in question (see figs 11, 12, 17, 18, 19, and 20).
     As demonstrated above then the officially announced dates for the solar events at Prasat Phanom Rung have had minor errors every year. Probably due to calculations based on the 'rule of thumb'. More exact results have continuously been published here and delivered in person to the director of Phanom Rung Historical Park and the Office for Tourism and Sport in Buriram.

The digital News Room of the Tourism Authorithy of Thailand informs:
I: ''Astro-archaeological Phenomenon at Prasat Hin Khao Phanom Rung
Astrologers have also predicted that an extraordinary astro-archaeological phenomenon will occur at sunrise during the April 3-5 period this year. The doors of the temple sanctuary are so perfectly aligned that during this period, at sunrise on a cloudless day with clear blue skies, the sun’s rays will shine through all fifteen doorways of the sanctuary in a single shaft of light. (Plan to arrive between sunrise and no later than 06.00 a.m.)''

Comments: The time is correct. The date is one day off (see figs 22 and 23).
     ''Astrologers have predicted...'' (?) Recalling the passage in the Holy Bible and the prediction of the birth of Jesus Christ: The wise men from the east , who had seen ''his star in the east, and are come to worship him."
     ''The doors of the temple sanctuary are so perfectly aligned...'' Towards what? The sun will rise aligned with any human structure oriented between 66° and 112° minimum once a year. Nearly all Khmer temples are orientated so that the sun will rise aligned with its structure.

Quote II: ''According to ancient folk belief, one should make a pilgrimage to the summit of Khao Phanom Rung to pay homage to the gods, deities and celestial beings that reside on the mountain at least once in a lifetime. The tradition has been carefully preserved by the residents of I-san over the centuries'.

Comments: The traditional date of the local old ceremony of ascending the mountain was ''the 15th ascending day in the lunar calendar in the fifth month'' = full moon in April. This practice is still an authentic event among the locals and mostly NOT coinciding with the solar event and the modern Light and Show Festival.
     Another ascending the mounting at full moon in April is preformed among the locals at another mountain temple only 11.4 km to the south east. And at other locations as well.
     Phanom Rung was apparently not a regional pilgrimage sanctuary. We do not know how old 'the full moon in April ceremony' is (old or ancient?). Neither do we know whether it has Khmer Hindu roots or not.

The Tourism Authority of Thailand also announces the annual solar event(s) at Phanom Rung on another web-site:
The text is identical to the text in the News Room above, except for the dating: In the News Room we are informed that the event is 3rd to 5th April, the second reference gives 1st and 2nd of April and ''no later than 07:30''...
Amazing!

Quote III: ''Although often overlooked on account of the famed Angkor city complex in Cambodia, the Khmer monuments of I-san represent key architectural milestones in the development of Angkorean design and ritual. In fact virtually every Angkor-period monument played a role in an elaborate cosmology that linked the entire network, a part of which lay in what is today Thailand.''

Comment: If the orientation of Prasat Phanom Rung has intended astronomical significance then this concept predates Angkor Wat 200 - 400 years.
''... an elaborate cosmology that linked the entire network''. Reference? The author is not aware of any academic research or scholarly publications on the subject ancient Khmer temples and eventual relation to archaeoastronomy.

Thai Text:

     ได้เรียนรู้ว่าในวันเดือน 5 ขึ้น 15 ค่ำนั้น เป็นวันที่พระอาทิตย์และพระจันทร์จะส่องแสงตอนเที่ยงวันทำมุมตั้งฉากกับพื้นโลกในบริเวณประเทศไทย ฉะนั้นจะพบเห็นพระอาทิตย์ขึ้นส่องแสงผ่านประตูทุกช่องทั้ง 15 ช่อง ตามแนวทิศตะวันออก-ตะวันตก ของปราสาทหินพนมรุ้ง และในเย็นวันขึ้น 15 ค่ำ เดือน 5 พระจันทร์จะขึ้นตรงกับช่องประตูทุกช่องเช่นเดียวกัน
     ในกรณีดังกล่าวอธิบายได้ว่า สถาปนิกหรือช่างก่อสร้างชาวขอมโบราณมีความรอบรู้เรื่องดาราศาสตร์มากและได้วางผังปราสาทโดยวางให้ตรงตามทิศตะวันออก-ตะวันตก โดยกำหนดเอาวันที่พระอาทิตย์ส่องแสงตั้งฉากกับพื้นโลกในบริเวณประเทศไทย นั่นคือพระอาทิตย์จะส่องแสงตั้งฉากกับพื้นโลกเวลาเที่ยงตรง (คนยืนกลางแจ้งจะไม่มีเงา) วันที่พระอาทิตย์ส่องแสงตั้งฉากกับพื้นโลกคือวันขึ้น 15 ค่ำ เดือน 5 ในพุทธศตวรรษที่ 15-16 (แต่ปัจจุบันพระอาทิตย์ได้ทำมุมเอียงไปบ้างแล้วตามวงโคจรของโลก พระอาทิตย์พระจันทร์ ได้ทำมุมเปลี่ยนไปตามระบบสุริยจักรวาล)
     ฉะนั้นจึงพบว่าชาวบ้านจะนิยมขึ้นเขาพนมรุ้งในวันเดือน 5 ขึ้น 15 ค่ำ หรือในวันใกล้เคียง เพื่อจะได้เห็นสิ่งมหัศจรรย์ดังกล่าวด้วย ครั้นมีผู้คนไปนมัสการสิ่งศักดิ์สิทธิ์ในวันดังกล่าวจำนวนมาก จึงมีผู้ริเริ่มทำบุญกุศลจัดงานนมัสการพระพุทธบาทจำลอง ปิดทองพระพุทธรูปแต่กระนั้นก็ตามยังไม่ได้จัดงานบุญกันสม่ำเสมอทุกปี

Partial translation:

     ''At noon on the 15th day in the 5th month (full moon in April) it will be the day when the sun and the moon will cast its rays making a right angle with the surface of the earth … therefore one will see the raising sun throwing its rays passing all 15 doors following east-western direction of Prasat Hin Phanom Rung. And at dusk on the 15th day in the 5th month the moon will raise straight in the same line of the doors''
   ''The ancient Khmer architects or the building-constructors had a very deep knowledge about astronomy and made the plan of the prasat in a straight east-west orientation, scheduling the day when the sun will cast its rays making a right angle with the surface of the earth in the Thai area, meaning that the sun will cast its rays making a right angle with the surface of the earth exactly at noon (a standing person will have no shadow) .. on the 15th day in the 5th month in the 15th-16th century B.E. (10th-11th A.D.) – (but nowadays the sun has been tilting a little bit following the encircling orbit of the world - the sun and the moon have been changing angle following the solar system'' (sic.))
     ''Therefore the rural people like to ascend Khao Phanom Rung on the 15th day of the 5th month or on a nearby day, because they will see miraculous things – so to say. When having people go and ’wai’ sacred objects'' … etc

     The text is difficult to translate as several astronomical concepts are mistakenly mixed up. Some of the errors are commented on below:
 

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