The James Webb Space Telescope has snapped its first in-focus image. The milestone comes after the mission team spent the last few weeks aligning its mirrors, and the telescope is now set to meet or even exceed its original science goals. It was also recently spotted by another spacecraft in the area.
The JWST is comprised of 18 big golden mirrors, which all gather light from cosmic sources and focus it onto the image sensor. After the rigors of launch and deployment, however, all of these mirrors were pointing in slightly different directions, so they needed to be aligned to focus on the same object.
And now that process is complete, bringing the primary imaging instrument, the Near-Infrared Camera, into alignment with the mirrors. The team tested how well the mirrors had aligned by pointing the telescope at a bright star called 2MASS J17554042+6551277, and sure enough the resulting image is crystal clear. In fact, it’s the highest resolution infrared image ever captured from space.
“We have fully aligned and focused the telescope on a star, and the performance is beating specifications,” said Ritva Keski-Kuha, deputy optical telescope element manager for Webb. “We are excited about what this means for science. We now know we have built the right telescope.”
The next phase of preparations involves aligning the mirrors to other instruments, including the Near-Infrared Spectrograph, Mid-Infrared Instrument, and Near Infrared Imager and Slitless Spectrograph. This process is on track to be completed by early May or sooner, the team says.
Meanwhile, another spacecraft actually snapped a photo of the James Webb Space Telescope while it was busy preparing itself. ESA’s Gaia observatory has been orbiting the same region in space – Lagrange point 2 – since 2014, scanning the entire sky every few months.
And on February 18, its new neighbor popped into view in one section of that sky map. At the time, the two spacecraft were 1 million km (621,370 miles) apart, with Webb’s big sunshield blocking most of the reflected light. As such, the JWST appears as just a faint speck of light to the left of the image.
While the JWST’s first in-focus image is a major milestone, the real treats will come around mid-2022, when the telescope’s first full-resolution images and science data begin to be released.
The team discusses how the alignment was achieved in the video below.