He said: "When I discovered that I had worked out the location where Constable painted this particular masterpiece, I couldn't believe it. All the pieces of the jigsaw finally fitted together."
Painted between 1814 and 1815, The Stour Valley And Dedham Village depicts Langham church, Dedham church, Fen Bridge and the bend in the River Stour.
Over time, hedge boundaries have moved and trees have become established, blocking out some of the buildings behind.
By studying the buildings and river as well as the East Bergholt Enclosure Map of 1817, Mr Atkinson found boundaries in place in 1817 had changed drastically by 1830.
He said: "Many had disappeared altogether and new hedges appeared at different angles. By plotting out where the field boundaries would once have been, we were able to pinpoint the exact location from which Constable painted this particular view."
Mr Atkinson added: "Most of Constable's landscapes painted in the Dedham Vale are now known, but questions do remain over some.
"This one in particular had confused us, but once we were able to identify the changes in the landscape, many of which had been made in Constable's lifetime, we were able to solve the 195-year mystery."
The Stour Valley And Dedham Village is now housed in the Museum of Fine Arts in Boston, US.
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