Kraison Siharat Hall is commonly known as Phra Thinang Yen or Thale Chup Son Hall, 4 kilometres from the centre of town. 

This hall is another residence of King Narai the Great. The hall is located on an island surrounded by Thale Chup Son, which was once a large reservoir surrounded with a dam made of stone and cement. King Narai the Great commanded its construction for relaxation. According to the French chronicle, when King Narai the Great hunted elephants in the east mountain, he would return and stay at this hall. The period of its construction was unknown. However, he also welcomed his honourable guests from France at this hall. Therefore, it must have been constructed prior to 1685.

It is a one-storey hall made of bricks and cement with a cruciform plan. There was a projecting windowed portico. The windows and doors are accented in the Ruean Kaeo style, a famous one during the reign of King Narai the Great. However, the only remain is the wall. 

Within the compound, there is a group of small brick buildings with pointed arched doors and windows. It is assumed to have been the residences of the guards. A mounting platform for getting on horses or elephants is situated in the front and at the back of the hall. 

Phra Thinang Yen is important in terms of astronomy because King Narai the Great utilised this place for an observation of the lunar eclipse on 11 December, 1685, and witnessed the solar eclipse on 30 April, 1688, with the Jesuit priests and the first group of envoys representing King Louise XIV of France. The reason of the hall’s usage to observe the lunar eclipse as stated in the French chronicle was because it was a suitable place where a panorama of the sky could be seen. Moreover, there was enough space for the installment of equipment. There is a painting of the lunar eclipse observation drawn by a Frenchman. In the painting, King Narai the Great wore a high-pinnacled hat, and witnessed the eclipse through a telescope placed on a tripod from the window of Phra Thinang Yen. On the balcony on one side of the window were crouching aristocrats, while on the other side sat astronomers, inspecting the phenomenon through telescopes. It can be said that modern astronomy happened for the first time in Thailand here at Phra Thinang Yen in Lop Buri. 

Thale Chup Son in the past was a low-lying wetland area. King Narai the Great commanded the construction of a large embankment to direct the stream from Thale Chup Son passing through the baked-clay pipe to Lop Buri. At present, a mound still appears. The admission fee is 50 baht. For more information, please contact Tel. 0 3641 3779, 0 3641 2510.