NASA Releases Progress Photos of James Webb Mirror Alignment

Yesterday, NASA released images showing the progress that Webb engineers have made in aligning the telescopes 18 hexagonal mirror segments. There are seven total phases in the mirror alignment process that must be completed over the next few months before James Webb is ready to begin making science observations, and the team has just completed the first three of them.

This gif shows the “before” and “after” images from Segment Alignment, when the team corrected large positioning errors of its primary mirror segments and updated the alignment of the secondary mirror. Credit: NASA/STScI

The first phase of mirror alignment for JWST after instruments onboard detected first light involved determining which mirror segments corresponded with points of light detected by the telescope. Since the mirror segments were all essentially facing different directions, rather than focusing the light into a single point, the first image of a single star appeared to be 18 points of light randomly scattered across the picture. The team then had to determine the mirror segment that each point of light come from so they could begin alignment.

Image of HD 84406 taken by JWST. Each point of light is the same star, just taken by mirror segments at different angles. Credit: NASA/STScl

After segment image identification was complete, the team began working on phases two and three, segment alignment and image stacking. Once Webb’s team identified each segment, they began moving each segment until they roughly formed the shape of the…