The images are a feast for the eyes. And thanks to a unique and dedicated effort by a team of writers and scientists, they’re a treat, too. for those who can’t see.

Images returning from the Webb Telescope all receive detailed alt-text descriptions – textual versions of the images that are turned into sound by screen reader software used by visually impaired people. Alt text is the keystone of an inclusive and web-accessible design, allowing users to access online resources in multiple ways. Alternate text for new Webb Telescope images is underway advertised as exemplary.

“The image is divided horizontally by a wavy line between a cloud forming a nebula along the lower part and a relatively bright upper part. Speckled on both sides is a star field, showing countless stars of different sizes. The smaller of them are small, distant, faint points of light. The larger of them appear larger, closer, brighter, and more fully resolved with 8-point diffraction peaks. upper part of image is bluish and has translucent wispy cloud-like streaks rising from the nebula below.The orange cloud formation in the lower half varies in density and ranges from translucent to opaque.Stars vary in color, the majority of which have a blue or orange tint.The nebula’s cloud-like structure contains ridges, peaks and valleys – a very chain-like appearance. and mountains. Three long diffraction spikes from the upper right edge of the image suggest the presence of a large star just out of view. [Image: NASA/ESA/CSA/STScI]

Alternate text is being written at the Space Telescope Science Institute (STScI) in Baltimore, Maryland, which leads science and mission operations for the Webb Telescope and partners with NASA. A team of about 15 writers, editors, astronomers and curators are now actively engaged in a detailed editorial process of analyzing the images returning from the telescope. They are now turning them into text which can then be interpreted by the visually impaired in their own visualizations.

Margaret W. Carruthers, associate branch director for writing and design at STScI, explains that the process of turning these images into text is a kind of design effort. “I view this writing as an engineering design issue,” she says. “In this case, we have these charts that are really important and convey a lot of information, but some people can’t access them.”

“Image of a group of five galaxies that appear close to each other in the sky: two in the middle, one up, one upper left, and one down. Four of the five seem to be touching. One is somewhat separate. In the image, the galaxies are large compared to the hundreds of much smaller (more distant) galaxies in the background. All five galaxies have bright white cores. Each has a slightly different size, shape, structure and coloration. Scattered across the image, in front of the galaxies are a number of prominent stars with diffraction spikes: bright white dots, each with eight bright lines radiating from the center. [Image: NASA/ESA/CSA/STScI]

Take, for example, this view of Stephan’s Quintet, a composite of near- and mid-infrared images showing the distant cluster of five galaxies, four of which are so close together that they bend in space under the sun. attraction to the other.

The alt text puts it into words: “Image of a group of five galaxies that appear close to each other in the sky: two in the middle, one up, one upper left, and one down. Four of the five seem to be touching. One is somewhat separate. In the image, the galaxies are large compared to the hundreds of much smaller (more distant) galaxies in the background. All five galaxies have bright white cores. Each has a slightly different size, shape, structure and coloration. Scattered across the image, in front of the galaxies, are a number of prominent stars with diffraction spikes: bright white dots, each with eight bright lines radiating from the center.

“Thousands of small galaxies appear through this view. Their colors vary. Some are shades of orange, while others are white. Most appear as fuzzy ovals, but a few have distinct spiral arms. In front of the galaxies are several prominent stars. Most appear blue, and bright stars have diffraction spikes, forming an eight-pointed star shape. There are also many thin, long, orange arcs that curve around the center of the image. [Image: NASA/ESA/CSA/STScI]

Carruthers notes that this text is only part of the package. Someone using a screen reader will also see the title of the image, along with the more explanatory caption that accompanies it, and sometimes even a full press release. Alt text, she says, tries to bridge the gaps between these other forms of text. It involves creating what she likens to a concept map of what’s in the picture. “We first try to give an overview, to give them an orientation. Then we go into the details, but we constantly refer to that concept map so people know what you’re talking about,” she says. Since screen readers are audio text, frequent reminders of this card help keep everything in context.

The team also found other tricks to make these alt text descriptions as useful as possible. Directional words are useful especially for explaining a variety of objects in relation to each other. Geometric terms, such as circles, diamonds, or swirls, are also important. And because the universe is constantly changing, says Carruthers, “you also have to convey the dynamic that you see in it, the sense of action.”

“Two views of the same object, the South Ring Nebula, are shown side by side. Both feature black backgrounds dotted with tiny bright stars and distant galaxies. Both show the planetary nebula as a slightly misshapen oval tilted from top left to bottom right. At left, the near-infrared image shows a bright white star with eight long diffraction peaks in the center. A large transparent teal oval surrounds the central star. Several red seashells surround the oval teal, extending almost to the edges of the image. The red layers, which are wavy overall, appear to have very thin straight lines running through them. On the right, the mid-infrared image shows two stars in the center very close together. The left one is red, the right one is light blue. The blue star is surrounded by tiny diffraction peaks. A large translucent red oval surrounds the central stars. From the red oval, the seashells extend into a mix of colors. [Image: NASA/ESA/CSA/STScI]

According to Tim Rhue II, Senior Informal Education Specialist at STScI, work on alternative texts is gaining more and more attention at STScI and NASA. “We’ve really taken a little deeper dive in the last couple of years or so,” he says. Originally, the system was only configured to allow very brief descriptions in the alt text of images, limited to just 60 characters, or the equivalent of the last 10 words of that sentence. A system upgrade extended that to 125 characters, which Carruthers likens to an old tweet. “It’s not enough,” she said.

This became very clear when the team started sharing some of these alt text descriptions with people who use screen readers. “When we started working more directly with people who were actually using these descriptions, we realized that wasn’t really best practice,” Rhue says. “So we decided, let’s bring this up.”

Now, alt text can be up to 1,024 characters, or about 350 words. Writing such a short description is a challenge. A big plus is to make the description accurately reflect what’s in the picture and create what is hopefully a similar image in the mind of the person reading it.

“I’m aiming for a description that you could take – without having seen the image – and you could sketch out something that looks pretty much like what we have,” says Carruthers.

In fact, Carruthers did this exercise: read his description to the other team members without showing them the image and ask them to draw what they visualized. “We could see, oh it worked well; but wait, they totally found something else when I used a particular word,” she says. “It really helped a lot with how to frame things.”

STScI received additional advice from Prime Access Consulting, a company that works with museums and other educational institutions on inclusive design and accessibility. Rhue says they helped create a specific style guide that STScI writers and editors can use to ensure future alt text descriptions are accessible and understandable. The alt-text creation team also includes an audience reviewer who is visually impaired, and Rhue hopes to increase the number of people with disabilities reviewing the text before it is published.

Rhue says it’s also important to make them interesting, which helps build the case for more science, and maybe even more people getting into science. “If we can generate descriptions that grab people’s attention and make them want more, then we’re doing our job,” he says.

As more and more images return from the Space Telescope during its planned decades-long mission, the team of writers, editors and astronomers will continue this process of translation and interpretation for each image posted to STScI websites. It is a multi-step process; the images collected by the Webb telescope are mostly in the infrared section of the electromagnetic spectrum, and therefore invisible to the human eye. These images must be processed for sighted people to see, and then processed again for the visually impaired.

Carruthers says this process is all about explaining the universe to people. “If nothing else, we have to be specific,” she says. “I think we can also be evocative and beautiful.”