James Webb’s engineers combined his 18 images into one

Work on preparing the James Webb Space Telescope for scientific data collection is still ongoing so that the telescope is ready to share its first beautiful images of space this summer. A long and delicate process alignment of the primary and secondary mirrors of the telescope continues, but engineers recently reached an important milestone when they completed the overlay phase.

Last week the engineers split an array of images showing 18 points of light. In fact it was 18 images of the same star, the bright star HD 84406, which was used for the alignment process, representing the 18 segments that make up the main mirror. Each segment reflected a star, and the overall shape corresponded to the overall hexagonal shape of the mirror. The next step, called segment alignment, was to make small adjustments to each of the mirror segments, and adjust the secondary mirror to make the 18 points of light sharper. NASA engineers shared a new image in a blog post this week.

Once this was done, the team could move on to the overlay process, in which 18 dots were superimposed on each other to create a single dot of light. This move means that the mirror now works as one large mirror instead of 18 small mirrors, but that doesn’t mean the adjustments are complete. The team still needs to make small adjustments in a phase called coarse phasing, in which different pairs of segments will be matched to correct small differences between segments, such as changes in their height.

“We still have work to do, but we are increasingly pleased with the results we are seeing,” said Lee Feinberg, manager of Webb optical telescope elements at NASA’s Goddard Space Flight Center. blog post. “Years of planning and testing pay dividends, and the team couldn’t be more excited to see what the next few weeks and months will bring.”

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