NASA unveiled the first fully focused photo of a star taken by the James Webb Telescope on March 16. The result is spectacular. The instrument performs as well as astronomers had dreamed.
“See how far you’ve come”, Nasa raves on Twitter. Posting a series of photos of the star HD84406the American space agency explains that it started, on February 2, with 18 scattered points, “18 reflections of the same star, each from one of Webb’s primary mirror segments. These points were then rearranged, stacked and refined”.
With the result, precise CBS News, that after weeks of aligning the telescope’s mirrors, the agency released “a razor-sharp photo of a nondescript star against a backdrop of more distant galaxies that shows the telescope’s optical system is working almost perfectly”.
Mirror alignment is still in progress. But the agency’s director of research, Thomas Zurbuchen, is over the moon:
It is one of the most magnificent days of my entire career at NASA. Today we can report that the optics system will perform to specification or even better.”
The Australian Magazine Cosmos explains why the feeling of relief was noticeable at NASA: “The telescope’s main mirror is 6.5 meters wide and is made up of 18 hexagonal segments that self-assemble in space. Aligning each of these segments to complete a single smooth reflective surface requires nanoscale precision. Until now, there was no way to confirm that the process was successful”.
To go back in time
The near infrared camera NIRCam is the only one of the four instruments of the telescope deployed 1.5 million kilometers from Earth to be in operation. According to NASA, the other three will be operational in June or July.
The James Webb Telescope will then be able to transmit images that “will allow us to go back in time to capture galaxies from the earliest days of our universe, just a few hundred million years after the Big Bang – potentially transforming our understanding of galaxy formation and evolution.”marvels Cosmos.
The English video below explains how the mirrors were aligned.
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Martin Gauthier