How Monet painted the time into his sunset Astronomer and physics professor Donald Olson said: "We like to use astronomy to show students how science can solve real-world puzzles," he said. We asked, 'Could we use the dramatic rocks in the landscape and the position of the setting sun to determine where and when, specifically, Monet created this beautiful masterpiece?' Monet painted a series of paintings featuring this stretch of the Normandy coast during his three-week visit to the area during the winter of 1883. With The Cliff, Étretat: Sunset, the artist painted a rock formation known as the Falaise d'Aval along with the arch Porte d'Aval overlapping a tall, needle-shaped rock spire known as Aiguille (the Needle) that stands just offshore. Cliffs at Etretat, Monet Of all the paintings Monet painted at Étretat, this is the only canvas that includes the disc of the sun, and that one detail opens the door to date the scene precisely. To determine on which days in February the sun would've set in the proper location for Monet to capture in his painting, the team of Texas State researchers traveled in August 2012 to France. The research team made extensive topographic measurements of the terrain at Étretat. To determine the exact locations where Monet stood. The Texas State team found that the view matched the scene depicted in Étretat: Sunset at only one location--a spot 425 yards from the Porte d'Amont on a rocky beach under an overhanging cliff The researchers then used planetarium software to compare the modern sky to that of the 19th century and calculated that the sun would have set along that path on Feb. 5, 1883. The group then combed through letters Monet wrote from Étretat during his stay, along with weather records and tide tables from February of 1883 to confirm their date. They discovered that on Feb. 3 Monet was working on nearby Jambourg Beach and that the artist spent all day Feb. 4 entertaining his visiting brother. The tides of Feb. 6 did not match the painting, and Monet's letters show that he paid close attention to the tides. On Feb. 7 cloudy weather and rain storms began. Through the process of elimination, the calculated date of Feb. 5 is the only one remaining that matches the sun's position, the weather and the tide level in the painting. Armed with that knowledge, the Texas State team used the height of the needle-like Aiguille formation to calculate the exact time from the altitude of the sun above the horizon. We were able to determine the month, day, hour and precise minute--accurate to plus or minus one minute--when Monet was inspired by that beautiful scene, Olson said. Monet observed this sunset on Feb. 5, 1883 at 4:53 p.m. local mean time.