Wat Mo Hon or the "Monastery of the Astrologer" was located off the city island in the southeastern area of Ayutthaya in Phai Ling sub-district. The temple was part of a cluster of temples situated east of Wat Yai Chai Mongkhon. No traces of the temple are left on ground level, but it was situated on a small mound clearly visible on the Ayutthaya aerial flood map from November 2011.
Wat Mo Hon was situated on the west bank of Khlong Pho (1), a canal splitting off from Khlong Khao Mao, east of Wat Krasang.
The site is only mentioned on a Fine Arts Department (FAD) map drafted in 1993. To my knowledge no excavation has been performed by FAD on this site. Wat Mo Hon was situated in Geo Coord: 14° 20' 54.72" N, 100° 36' 8.10" E (approximately).
Not confirmed as yet, but Khlong Pho could have been connected to Ban Pho in Bang Pa-In district and exit into the Chao Phraya River opposite Ko Phra in a location called "Ban Kedam" by the Dutch or "Krasen" on 17-18th C maps.
(Extract of a 1993 Fine Arts Department map - Courtesy Khun Supot Prommanot, Director of the 3th Regional Office of Fine Arts)