This “selfie” was created using a specialized pupil imaging lens inside of the NIRCam instrument that was designed to take images of the primary mirror segments instead of images of space. (NASA)
By Denise Chow
A million miles from Earth, the James Webb Telescope has snapped its first selfie from orbit.
NASA released the self-portrait Friday, along with several mosaic images that the telescope captured while gazing at its first star. The images were taken as part of a monthslong process to assess the health of the observatory’s various mirrors and instruments.
Nearly 50 days after Webb launched into space, the photos are early indicators that it is functioning as expected and is ready to begin its mission.
“This amazing telescope has not only spread its wings, but it has now opened its eyes,” Lee Feinberg, Webb’s optical telescope element manager at the NASA Goddard Space Flight Center in Greenbelt, Maryland, said Friday in a news briefing.
But before Webb can begin capturing jaw-dropping images of galaxies, star clusters and planets, mission controllers need to be sure that the observatory’s huge primary mirror is properly aligned.
Measuring more than 21 feet across, its honeycomb-shaped primary mirror is designed to collect and focus light from objects in the cosmos. To fit inside its rocket for launch, however, the telescope’s mirror, along with several other components, were carefully folded up.
Over the course of several weeks, as the telescope journeyed to its final destination in orbit around the sun, it delicately unfurled. Each of the telescope’s 18 gold-coated, hexagonal mirror segments were moved into place.
In the newly released images, scientists used Webb’s infrared camera, known as NIRCam, to look at starlight from the same star in each of the telescope’s 18 primary mirror segments.
The mosaics show 18 randomly organized, blurry dots of starlight, representing Webb’s unaligned mirror segments reflecting light from the same star back at the telescope’s secondary mirror and into NIRCam’s detectors.
“For the first time in flight, all of these systems acted together in the way that they will for science observations,” said Marshall Perrin, Webb’s deputy telescope scientist at the Space Telescope Science Institute in Baltimore.
He added that this initial exercise, which included taking more than 1,500 photos, went “very, very smoothly,” and that the resulting images were “a real ‘wow’ moment.”
“Just lots of tears and excitement from everybody there in the room,” Perrin said.
Over the coming months, Webb’s instruments will be fully calibrated and its primary mirror will need to achieve an ultraprecise alignment to function as one single entity. Once that happens, its images will become clearer and packed with more detail. The mission’s first scientific images are expected to be released in the summer, NASA said.
So far, the $10 billion observatory appears to be healthy and operating well, but Feinberg said there’s still much more work to be done.
“This is still early, but we are very encouraged with what we’re seeing,” he said.
Billed as the successor to the iconic Hubble Space Telescope, Webb is designed to unlock mysteries of the early universe by seeing deeper into space and in greater detail than any telescope that has come before it.
The observatory is the world’s largest and most sophisticated space telescope, and is expected to be able to study the oldest and most distant objects in the universe, as far back as 100 million years after the Big Bang.