As #Webb is going through the focusing of its mirrors, let's look into what this process entails. #WebbSeesFarther 👇
1/ #Webb's 18 hexagonal mirrors have already been unfolded a while back, but now it's time for a more precise alignment so they point in exactly the same direction 🎯 and deliver sharp images.
📷 NASA/Chris Gunn
📷 NASA/Chris Gunn
2/ These corrections are made through a process called 〰️ wavefront sensing and control, which senses and corrects any errors in the telescope's optics, aligning the mirrors to within tens of nanometres
3/ The development of this technology is benefiting not only #Webb, but us on Earth too thanks to a spinoff for diagnosing eye conditions and accurate mapping of the eye.
4/ This spinoff supports
👉 research in cataracts, keratoconus — an eye condition that causes reduced vision, and eye movement
👉 improvements in the LASIK procedure
👉 research in cataracts, keratoconus — an eye condition that causes reduced vision, and eye movement
👉 improvements in the LASIK procedure
5/ During the wavefront sending process, a wavefront sensor, NIRCam in this case, measures any imperfections in the alignment of the mirror segments that prevent them from acting like a single, 6.5-meter mirror.
6/ Engineers will use NIRCam to take 18 out-of-focus images of a star, one from each mirror segment. Using computer algorithms they will determine the overall shape of the primary mirror & how they must move the mirrors to align them.
7. Actuators behind each mirror enable the aligning. The actuators can move in steps that are about 1/10.000th the diametre of a human hair. See more here:
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