A hexagonal array of James Webb images shows the shape of his mirror


We will not yet see stunning images of space from the James Webb Space Telescope, as the telescope is still undergoing a months-long process of aligning mirrors. However, there are still interesting updates that are coming, and the last step is a new image of the star HD 84406, shown 18 times in a hexagonal image array.

Web’s first drawing was released last week, and in this image you can see 18 points of light representing the same star reflected 18 times, thanks to the 18 hexagonal segments that make up the telescope’s main mirror. Since the segments are still aligned, in this image they are distributed across the image.

This early alignment of the Web with starlight points arranged in a honeycomb shape of the main mirror is called an “array of images”. NASA / STScI / J. DePasquale

Now, in this new image, you can see 18 points of light arranged in a hexagonal shape, which is a hexagonal mirror shape. This is due to the completion of the first phase of mirror alignment, called “Segment Image Identification”. This allows you to place points of light in an array of images.

“We’re directing the segment points into this array so that they are in the same location as the physical mirrors,” said Matthew Lala, a systems scientist and telescope manager at the Space Telescope Institute. statement. “During global image alignment and stacking, this familiar structure gives the wavefront team an intuitive and natural way to visualize changes in segment spots in the context of the entire main mirror. Now we can see how the main mirror is slowly gaining its exact intended shape! ”

The next stage is mirror alignment process called segment alignment. In this phase, each segment of the mirror will adjust its position to accommodate larger positioning errors, and will be adjusted secondary mirror – a round mirror located at the end of the rod. When this is done, every point of light representing the star will become more focused. The team can then move on to the image overlay phase, in which each of the 18 individual points of light is applied to each other to create a single point.

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A hexagonal array of James Webb images shows the shape of his mirror

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