Webb’s space telescope is pointing at one particular star. What’s so interesting about her? Almost nothing, except for the fact that it is visible to the telescope continuously and has a constant brightness. NASA therefore chose it for initial setup and calibration of mirrors. Now the telescope has moved a little closer to being able to explore the secrets of deep space.
Recently published photo, resp. collage of images, showed one and the same star in 18 different positions. The James Webb Space Telescope has an 18-segment mirror that needs to be calibrated first. Now, scientists have released another image, in which the images are already arranged exactly as the individual mirrors see the star.
The James Webb Space Telescope (JWST) has taken another small, but important, step. After identifying the individual segments of the primary mirror, they managed to set them in the correct position for the next step, which is focusing. We’re still looking at star HD84406 from the Big Dipper. pic.twitter.com/BcmD5rKY76
– Michal Vaclavik (@Kosmo_Michal) February 21, 2022
In the image above, you can see that the arrangement exactly matches the hexagonal shape of the JWST mirror system. All the objects in the picture are one and the same star HD84406 from the constellation Ursa Major, but it is always reflected by another of the 18 mirrors. As you can see, the mirrors are not yet fully focused or adjusted so that the reflected light comes together at one point.
Why didn’t we send one large mirror into space instead of 18 small ones?
If you wonder why humanity did not send one large mirror with a diameter of 6.5 meters into space, the answer is simple. The problem would be not only the production of such a mirror itself, but especially its safe introduction into space.
On Monday, January 24, 2022, the James Webb Space Telescope arrived in L2 orbit approximately 1.5 million kilometers from Earth.Photo: Courtesy of NASA
–
The solution was to divide the mirror into smaller segments. When all these small mirrors are adjusted, they will work like one big one. However, this requires that it be placed in the correct position with an error of less than 50 nanometers, i.e. about 1/10 of the wavelength of visible light. Achieving this value is a slow process that will take much longer than the actual placement of the sunshield and the initial layout of the mirrors. That’s why scientists expect that the first scientifically useful images will not arrive on Earth until mid-2022.
Source: NASA
–
/nginx/o/2020/01/28/12901022t1hffbb.jpg?resize=150%2C150&ssl=1 "Conducting classes in a state of affect: Liena Šomasei has to explain to the police – Celebrities – Apollo.lv – Entertainment")