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The unexpected star of NASA’s Webb images — the alt text descriptions

A team in Baltimore was responsible for the words that made the stunning photos accessible to everyone

Perspective by
Metro columnist
July 20, 2022 at 5:09 p.m. EDT
This image released by NASA on Tuesday, July 12, 2022, shows the edge of a nearby, young, star-forming region NGC 3324 in the Carina Nebula. Captured in infrared light by the Near-Infrared Camera on the James Webb Space Telescope, this image reveals previously obscured areas of star birth, according to NASA.
This image released by NASA on July 12 was captured by the James Webb Space Telescope. (AP)
5 min

In the days since NASA publicly shared stunning images captured by the James Webb Space Telescope, people have oohed and aahed. They have marveled at the breathtaking beauty of those photos and the significant lessons about the universe that might exist in those crisp cosmic details.

But it’s not only the photos that have wowed people.

Many have also been struck by the thoughtful descriptions that have accompanied them.

“If anyone ever tells you alt text isn’t important, show them @NASA’s alt text for the #WebbSpaceTelescope images,” Kate Meyers Emery tweeted. “They are able to convey the wonders and beauty of these in words, making these breathtaking views accessible.”

“This isn’t just a stunning picture from @NASA, it’s a brilliant example of how to use alt text,” the Royal National Institute of Blind People tweeted. “Do you agree?”

“It’s clear that the NASA digital team put a lot of thought and care into how they described the Webb Telescope images, and their descriptions feel like a love letter to space exploration and the infinite marvels of the universe,” Alexa Heinrich, of Accessible Social, wrote in an emailed newsletter. “Accessibility expands the world for everyone, making even distant stars attainable. It’s a beautiful thing indeed.”

The alt text feature on social media platforms allows a person to describe through words an image so that someone who is blind or visually impaired can use screen-reader technology to know what is being shown. In other words, it makes an image accessible to everyone. And in the case of the recent photos shared by NASA, it allowed everyone to know they were looking at celestial scenes bursting with colors and shapes.

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NASA, of course, should have included those descriptions with its photos. That it did was not surprising. What proved unexpected was how poetically striking and scientifically accurate those descriptions ended up being.

“The image is divided horizontally by an undulating line between a cloudscape forming a nebula along the bottom portion and a comparatively clear upper portion,” reads one. “Speckled across both portions is a starfield, showing innumerable stars of many sizes. The smallest of these are small, distant, and faint points of light. The largest of these appear larger, closer, brighter, and more fully resolved with 8-point diffraction spikes. The upper portion of the image is bluish, and has wispy translucent cloudlike streaks rising from the nebula below.”

That description can be appreciated by someone who is blind or someone who wants to know more about astronomy or anyone who appreciates the care that goes into choosing just the right word.

If you don’t need alt text to interpret an image, it’s easy to look past that feature. But the conversations that the NASA photos have encouraged are important, because they show how little it takes to bring more people into an experience.

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The team that produced those descriptions works for the Space Telescope Science Institute out of Baltimore, and they have been paying attention to the response.

“It’s been really heartening to see how much this has touched people,” said Tim Rhue II, the principal informal education specialist at the Space Telescope Science Institute. “It’s something that’s deeply personal to so many people. On top of that, we do it because we want to make astronomy accessible to everyone. It’s astronomy and dinosaurs that are gateways to science for so many people.”

A team that included writers, designers, scientists and educators worked together to put together the package of images the public saw, and the alt text was not an afterthought, Rhue said. He said the team had a relatively short period of time to produce those descriptions. He only saw the photos a week before the public did. But they had spent the previous two years discussing accessibility and working with a consulting agency to create an alt text stylebook. During that process, they practiced writing descriptions and learned what didn’t work.

“I had thought that brevity was a really important thing. That’s a common misconception,” Rhue said. He pointed to the saying “a picture is worth a thousand words” and said the recent images required more words than that to fully capture them. “There were more than 1,000 words written about each of those pictures, and we could keep going.”

The extended descriptions and alt text for the images can be found by clicking on the gallery on the Webb Space Telescope website. One alt text begins: “Two views of the same object, the Southern Ring Nebula, are shown side by side. Both feature black backgrounds speckled with tiny bright stars and distant galaxies. Both show the planetary nebula as a misshapen oval that is slightly angled from top left to bottom right.”

Rhue said that the team has heard from the public through email, social media and the website, and that for him, the personal stories have been the most powerful.

“As a blind person who has had dreams of doing astronomy since I was 6 … thank you to whoever not only remembered to write alt text for this — but did so in such a beautiful way,” software developer and accessibility activist Katie Durden wrote on Twitter. “I’ll likely never know who you are. But you touched my heart this day, alt-text writer.”

After Kelly Lepo tweeted that she was a member of the “small team” at the Space Telescope Science Institute who created the alt text, Durden shared that tweet and wrote of having dreamed since childhood of being able to see the stars.

“Y’all brought me closer to that dream than ever with your alt text,” Durden wrote. “I don’t have the words to say thank you.”