The most powerful, complicated, and expensive space observation station has sent in its first set of pictures after a nerve-wracking launch and trip to its permanent location.
The James Webb Space Telescope (JWST) has finally sent a batch of pictures captured with its 6.5-meter lens. NASA released a mosaic of the images as it tries to adjust the individual 18 lenses.
The image is blurry because NASA has to adjust the lenses first to take sharp pictures of the universe. While there are 18 light points in the photo, they represent the same star, the HD 84406, as it appears to each mirror segment. The scientists will use the Near Infrared Camera or NIRCam to fix any optical errors during the alignment process.
NASA spent 25 hours capturing the light that produced the mosaic image. It also required more than 1,500 images of the HD 84406 star to create the 18 points of light visible in the final image. Altogether, it processed 54 gigabytes of data.
This initial image is the foundation that NASA will use to align and focus the telescope. It achieved a dual purpose of confirming the NIRCam was ok to capture light from celestial figures and identify starlight from the same star coming in from each of the 18 primary mirror segments.
“This initial search covered an area about the size of the full Moon because the segment dots could potentially have been that spread out on the sky,” said Marshall Perrin, deputy telescope scientist for Webb and astronomer at the Space Telescope Science Institute. “Taking so much data right on the first day required all of Webb’s science operations and data processing systems here on Earth working smoothly with the observatory in space right from the start. And we found light from all 18 segments very near the center early in that search! This is a great starting point for mirror alignment.”
Commenting on the importance of the alignment process, Michael McElwain, observatory project scientist for the JWST, said, “Launching Webb to space was, of course, an exciting event, but for scientists and optical engineers, this is a pinnacle moment, when light from a star is successfully making its way through the system down onto a detector.”
Aligning the mirrors is a long process that might take months, but all 18 mirrors will eventually work as a single unit. The first set of working pictures is expected in this year’s summer.
The mirrors are one of the reasons the JWST is so complex. Each one must be positioned accurately, or the telescope won’t function properly. The engineers had to design it to fold to fit in the launch rocket.
The JWST also had a unique sun shield to protect it from the heat from the star. The shied, made up of five layers that must also be accurately positioned, is the size of a tennis court. It also had to be folded during the launch to unfurl during the trip to its present location in the Lagrange L2 ring, where it will orbit the sun. Protection from the sun is vital so that heat does not cause interference to the infrared process used to function.
It took the space telescope a month to reach its permanent location, about a million miles away. The distance makes it impossible to visit if a fix or repair is warranted. Even refueling is not actively planned for now, although there is enough fuel to power a 20-year mission.
During that time, the JWST will study ancient stars to discover how they formed and help search for exoplanets that might contain life.