Before the first full-color images from the James Webb Space Telescope were released to the world Tuesday, and before President Biden proudly unveiled the Webb’s photo of galaxy cluster SMACS 0723, Joseph DePasquale sat for hours in his office in Baltimore, working tirelessly to get them ready.
DePasquale, senior science visuals developer in the office of public outreach at the Space Telescope Science Institute, located on the Johns Hopkins University’s Homewood campus, was part of a team tasked with processing the Webb’s first photos — turning them from data sets to color images.
Tuesday marked the culmination of more than three decades of work on the James Webb Space Telescope. DePasquale is one of thousands from across the world who have been involved in the project at one point or another since its inception in 1989.
The James Webb Telescope is “the largest and most complex observatory ever launched into space,” according to the Space Telescope Science Institute, and was launched on December 25, 2021 from French Guiana to its target, about a million miles from Earth, according to NASA.
Webb will be able to observe formations of galaxies and stars from more than 13 billion years ago, and will help astronomers learn more about how the universe was formed. That’s due to the Webb’s ability to capture infrared light — whereas its predecessor, the Hubble Telescope, could primarily see visible and ultraviolet wavelengths. That means the Webb can detect light with longer wavelengths, and thus, from further back in time. It may also help scientists better understand the atmospheres of planets, as well as whether there may be a possibility of life forming there.
“Today, the hidden universe comes into view, and our understanding of the cosmos will be altered forever,” Kenneth Sembach, director of the Space Telescope Science Institute, or STScI, said Tuesday morning. “We’re at a turning point. There’s the universe we knew yesterday, before Webb, and a universe we know today. This isn’t an incremental advance in our understanding that we’re talking about, it’s revolutionary, transformative.”
The telescope’s first images show galaxy cluster SMACS 0723, reveal emerging stellar nurseries and individual stars in the Carina Nebula’s “Cosmic Cliffs,” and never-before-seen details of a galaxy group known as “Stephan’s Quintet.”
Images many light years away are captured by the Webb’s roughly 21-foot segmented mirror, protected by a large sun shield to keep it cold. They then “nestle their way into some detector … and then they’re sent across the million-mile chasm back to us, and to be housed in our archives here, in the building,” DePasquale said, referring to the Space Telescope Science Institute in Baltimore, “and then disseminated to the rest of the world.”
At the beginning of June, the data sets started to roll in. And DePasquale got to work. He worked seven days a week, even on Father’s Day and July 4, he said. He met every day at 9:30 a.m. with other members of the early release observations implementation team — including writers, designers, scientists and subject matter experts, he said.
“It’s been a long six weeks,” DePasquale said. “There was a lot of pressure to get things done and on time, and it really is such a relief.”
DePasquale was among those at the Space Telescope Science Institute Tuesday morning to speak about his work and reveal the telescope’s stunning first images.
“It was kind of emotional this morning, getting through the conference and seeing the public reactions,” DePasquale said. “It’s been intense to say the least.”
DePasquale remembers the first Webb data set he ever saw. He was in a conference room at the STScI with several others.
“It was just a black-and-white image, and colored it orange — astronomers love to do that,” DePasquale said. “And it was just incredible. You could tell right away, like, there’s so much detail in this image, I can’t believe that we’re seeing this now. Like, it really works, and look what we can do.”
DePasquale’s job was to transform those original data sets to the full-color images that were released to the world Tuesday morning. He was part of a two-person team who split up the images, and was the first person to see some of those full-color images on a computer screen in his office.
The first step of that process for many photos, DePasquale said, is “to pre-process the data, and get as clean a version of the image as possible.” That’s done by instrument scientists, he said.
After that, DePasquale’s work starts.
The final version of the deep-field image of SMACS 0723, revealed by President Biden, took DePasquale four hours from start to finish, he said.
“But that was after having gone through four iterations,” he said, involving adjustments from DePasquale as well as Anton Koekemoer, a research astronomer and observatory scientist who produced calibrated image files from the near infrared camera, or NIRcam.
“The first version of the image is embarrassingly bad,” DePasquale said. It had a lot of issues that needed to be cleaned up.
He was huddled over his office computer, pulling up variations of the image.
One issue, he said, was the background variations they discovered, especially in short wavelength channels. That meant he was seeing big blue squares in the image’s background.
“I had to go in and literally in Photoshop, make boxes and use curve adjustments to lower the blue, and try to balance the background as much as I could,” he said.
“The galaxies in this corner, the colors are completely wrong,” he said, pointing to the screen. “You can also clearly see the alignment issues. We zoom in here and we’re seeing like, multiple versions of colors of the different objects.”
In PixInsight and Photoshop, two of the main software applications he uses for image processing, DePasquale cleaned up the images using many different tools, including color balancing, sharpening, and more.
Also getting the images ready for release was Susan Mullally, the James Webb Space Telescope’s deputy project scientist at STScl.
That role “puts me on the sort of interface between what we do here at the institute to operate the telescope, and then the scientific community … to make sure the telescope is taking the observations it needs,” Mullally said.
That involves a lot of coordination, she said. She has to have the interests of many different scientific communities in mind.
“This telescope has a lot of capabilities. There’s 17 different observing modes on it. And each of them serves a different community of astronomers who are trying to answer different questions,” she said.
Right now, she’s been focusing on getting the archive ready for scientists to access to telescope’s data, and instructing those scientists on how to do so.
It’s “lots of little things,” she said, details that are coming together at the last moment.
Mullally said she has an important reminder for the public.
“We’re operating this telescope from here in Baltimore. We are the home of JWST. And so, if you’re ever walking by our building, you’re right next to where someone is directly communicating with the Webb Space Telescope.”