Located within King Narai's Palace, this museum houses vital artifacts related to the "Phra Thinang Kraisorn Siharat" site. It features historical sketches and replicated astronomical instruments used for observing lunar eclipses during the Ayutthaya period. Visitors can explore the diplomatic history between Siam and France through a wide and valuable range of displayed artifacts. The museum also exhibits antiquities from across Lopburi, reflecting the comprehensive Khmer and Ayutthaya civilizations in one place. It is an essential destination that clarifies the grand history of the palace and ancient astronomical systems for modern visitors.