Categories: AstronomyNewsScience

Astronomers Do the Math to Figure Out Exactly When Johannes Vermeer Painted this, More than 350 Years Ago

Most of us will be forgotten only a generation or two after we pass. But some few of us will be remembered: great scientists, leaders, or generals, for example. But we can add history’s great artists to that list, and one in particular: Johannes Vermeer.

Vermeer was largely ignored during the two centures that followed his death, and died as other painters often did: penniless. But as more time has passed, the Dutch Baroque painter has grown in reputation, as historians increasingly recognize him as a master.

Though it’s not Vermeer’s best-known work, “View of Delft” has become recognized as a masterpiece in more modern times. There’s a long-standing mystery around Vermeer’s masterpiece: when exactly was it painted?

Historians have thought for a long time that he painted it sometime during late spring or early summer of 1660. But Vermeer is considered a master of light and shadow in his work. Many scholars have tried to figure out the lighting in the painting, and at what time of day the scene is based on.

Now a team of researchers might have figured it out. The team is led by Texas State University astronomer, and physics professor emeritus Donald Olson. Their work was published in the September 2020 issue of the magazine Sky and Telescope. It’s titled “Dating Vermeer’s View of Delft.”

Some say that in the painting the light was coming from the west. Others say the Sun was directly overhead in the scene. After looking over maps of Delft, Olson and his students realized that the view is looking North. After figuring that out, it was clear that the light was coming from the southeast, making this a morning scene. This lines up with what some previous authors have concluded.

This is the only supposed portrait of Jan Vermeer. This is an enlarged detail of Vermeer’s painting The Procuress. Image Credit: By Johannes Vermeer – EQGpQpHextOEEg at Google Cultural Institute maximum zoom level, Public Domain,

In a press release from Texas State University, Professor Olson said “The students and I worked for about a year on this project. We spent a lot of time studying the topography of the town, using maps from the 17th and 19th centuries and Google Earth. We planned out exactly what we should do. On this research trip, it was the students who told us where to go to find Vermeer’s viewpoint and when to be there.”

The team would not have figured this out without Google Earth, or at least not as easily. It helped the students—Charles Condos and Michael Sánchez from Texas State, and Tim Jenison of San Antonio—map out the landmarks in the painting. Then they determined the angles of view that were closest to what Vermeer would have seen centuries ago.

The team also concluded that Vermeer’s vantage point was the second floor of an inn overlooking Delft.

“Google Earth is spectacularly accurate when it comes to distances and angles, so we used it as our measuring stick,” Sánchez said. “Google Earth is basically another tool in our arsenal of techniques.”

“I’d known about Dr. Olson’s work for quite some time, and it’s always fascinated me,” Sanchez said. “Combining my appreciation for art and love of astronomy appealed to me. When he approached me about this project, I was excited.”

One key to the work was the presence of a landmark in the painting called Nieuwe Kerk (New Church). It’s an octagonal tower, and it’s a feature in Delft now as it was in Vermeer’s time. Some historians have said that Vermeer enlarged the tower in his painting, and the team wanted to test that claim as part of their work.

Nieuwe Kerk in Delft, with its octagonal tower. The tower was critical to figuring out when Vermeer painted “View of Delft.” Image Credit: By Michielverbeek – Own work, CC BY-SA 4.0,

The painting itself is at the Mauritshuis museum in The Hague. Olson and the others visited the museum and took detailed measurements of the work. Then they compared their measurements with high-res photographs of the tower from a similar vantage point. After also taking measurements of the tower itself, they found that Vermeer in fact had not exagerrated the tower.

Understanding that Vermeer painted the tower as it was, was key to the team’s overall work. The octagonal tower has stone columns that project from the corners. In Vermeer’s painting, the center column almost, but not quite, shades the column to the left. A thin vertical sliver of light just grazes past the center column and lights up the left column. The presence of that detail allowed the astronomers to calculate the angle of the sun with great precision.

“Vermeer is known to have worked slowly. Completing all the details on the large canvas of his masterpiece may have taken weeks, months or even years.”

Professor Donald Olson, Texas State University

Vermeer is a master of light and shadow, and that little detailed sliver of light was the critical clue in solving this mystery.

“That’s our key. That’s the sensitive indicator of where the sun has to be to do that, to just skim the one projection and illuminate the other,” Olson said. “The pattern of light and shadows was a sensitive indicator of the position of the sun.”

A zoomed-in view of Vermeer’s “View of Delft” showing the octagonal tower at Nieuwe Kerk (New Church), in Delft. The tower and its shadows were key to solving the puzzle about the painting. Image Credit: By Johannes Vermeer – : Home : Info : : Image, Public Domain,

Once the team had a solid understanding of the time of day that Vermeer painted Delft at, a bunch of other details fell into place. One of those details was the clock on the facade of a building. People have placed the hands at just past 7 o’clock. But the team wasn’t sure.

The team of researchers had reviewed other paintings from the same time period, and noticed that in all other paintings with clocks, both hands were lined up as well. After more research, they discovered that clocks didn’t have minute hands until late 19th century. As it turns out, clocks in Vermeer’s time only had one hand—the hour hand.

With that knowledge in hand, the team realized that the clock in “View of Delft” had only one hand, pointing to a time near 8 AM.

A zoom-in of Vermeer’s “View of Delft” showing the clock on the facade of a building. It’s difficult to make out, but clocks only had an hour hand in Vermeer’s time, and this one is pointing to about 8 AM. Image Credit: By Johannes Vermeer – : Home: Info: Image, Public Domain,

Another clue was present in Nieuwe Kerk too. In Vermeer’s painting, the belfry openings are clear, whereas the present-day building has bells in the openings. The team consulted historical records, which showed that the carillon and bells were installed starting in April 1660 and was completed by September of the same year. So Vermeer had to have painted the city prior to that.

On the left, a modern day photo of Nieuwe Kerk, and on the right, “View of Delft” by Vermeer. The photo shows the bells that were installed in 1660, and the painting has none. Image: Left: By Michielverbeek – Own work, CC BY-SA 4.0, Right: “View of Delft” by Vermeer.

The team of researchers wasn’t finished yet, and as astronomers, they had more tools at their disposal than most art historians do.

They used astronomical software to calculate when the Sun would have been in the right position to cast the shadows on the towers in the painting. There were two answers, but only two. It was either April 6th to 8th, or September 3rd to 4th. But the trees are covered in leaves, which was the final clue. In Delft’s climate, the trees would not have burst into full leaf in early April, whereas they would be fully leafed in early September.

This zoomed-in view of Vermeer’s “View of Delft” shows trees in full leaf. Image Credit: By Johannes Vermeer – : Home : Info : : Image, Public Domain,

The team had their answer. Vermeer painted “View of Delft” as it appeared on September 3rd-4th, 1659. Or at a similar date on some year just prior to that.

“Vermeer is known to have worked slowly. Completing all the details on the large canvas of his masterpiece may have taken weeks, months or even years,” Olson said. “His remarkably accurate depiction of the distinctive and fleeting pattern of light and shadows on the Nieuwe Kerk suggests that at least this detail was inspired by direct observation of the sunlit tower rising above the wall and roofs of Delft.”


Evan Gough

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