- JWST snaps thousands of photos of our universe, from sparkling stellar nurseries to clusters of distant galaxies.
- But it takes human image processors, like Joe DePasquale, to turn these photos into works of art.
Two years ago today, NASA unveiled the first full-color space images captured by the James Webb Space Telescope.
We often hear about the scientists who study JWST's space images and what they discover, but behind these beautiful works of art are image processors like Joe DePasquale who can spend days, or even weeks, transforming a single image.
Webb's raw telescope images can look like empty black boxes when they first beam back to Earth. It takes science, intuition, and sometimes a bit of Photoshop to tease out the most important moments, DePasquale said.
DePasquale is a principal science visuals developer at the Space Telescope Science Institute. He processed some of the very first Webb images that the public got to see.
While working on an image, DePasquale gradually unveils details that sometimes amaze him. For the Deep Field image, one of Webb's first images, he was astonished to see tiny dots around some galaxies at the center. These dots are globular clusters of stars that surround very distant galaxies.
"To be able to pull out that much detail in just this tiny part of the sky — seeing that in such clarity was amazing," DePasquale said.
Unprecedented detail
After Webb launched in 2021, the next few months were "nail-biting," DePasquale said. Before the telescope could begin photographing the farthest reaches of the cosmos, it had to unfold and fully deploy in space.
"We watched every step along the way — the mirrors unfolding, the sunshield deploying, all of these things happening. There were 300 different single points of failure where if anything didn't work, the whole observatory would just be scrapped," he said.
Webb deployed perfectly, and got to work photographing our vast universe. A single Webb photo, like the Deep Field image, can capture thousands of galaxies.
Pulling all that detail out of the raw Webb image was no easy task. The final photo is actually four different images stitched together. When DePasquale first lined them up, he noticed that the brightness was different in each panel. To get them to match, he had to use Photoshop to adjust the lighting of the panels by hand.
It took about two weeks to process the Deep Field image from start to finish, he said. The end result is a sparkling portrait of the galaxy cluster SMACS 0723.
Peering across the universe
Webb is the most powerful telescope ever launched into space. It can see what the universe looked like around a quarter of a billion years after the Big Bang, when the first stars and galaxies started to form.
In its last two years of observations, Webb has fundamentally changed our understanding of the universe with groundbreaking discoveries like capturing the first images of stars forming inside the Pillars of Creation and the four most distant galaxies ever observed.
"Both Hubble and Webb are extremely high-angular-resolution telescopes. They're able to resolve very small details in these really distant objects," like the Tarantula Nebula, DePasquale told Business Insider.
The Tarantula Nebula is a star-forming cloud of gas and dust located in the Large Magellanic Cloud galaxy, 170,000 light-years away from Earth. That's really far away, but the extremely high precision of Webb's huge mirror allows the telescope to collect a lot of light from any object it observes, so it can photograph distant objects in striking detail, DePasquale said.
Processing raw space images is both a science and an art.
When processing the Tarantula Nebula image, DePasquale wanted to emphasize the cluster of hot, young stars in the center. To do that, he enhanced the contrast between the light and dark parts of the image, and made the billowing clouds of the nebula glow in whites and made the young stars burn bright blue. He does a lot of this work by hand, manipulating the images using Photoshop.
"Our work transitions from being analytical and scientific into a more subjective realm, where it's more like a photographer. We make scientifically-informed aesthetic judgments about how to process the data to highlight key scientific features within it," he said.