1560 images, 54 gigabytes of data, webber’s first shot released!Learn the secrets of Webber’s focus today!

2022-04-24 0 By

Space telescopes can be said to be the main observation tools of astronomers.The most famous of these is the Hubble Telescope, which we have been exposed to since childhood.In 1990, the career of Hubble, the most powerful optical telescope in human history, began.In its 18 years of service, Hubble has made a huge contribution to the advancement of astronomy by capturing breathtaking images of exploding galaxies in the universe.On December 25, 2021, the James Webb Space Telescope officially joined the Space Telescope Club, picking up the baton from the Hubble Telescope.As Hubble’s successor, James Webb is named after NASA’s second administrator, James Webb.During his tenure as HEAD of NASA, the United States opened a new chapter in space, including moon exploration and the Apollo moon program.On the evening of February 11, 2022, NASA officially released the first image taken by the Webb Telescope.JWST successfully took and sent back the first set of photos of stars and the first “selfie”.The first set of stellar images shows starlight from the same star captured by the Webb telescope’s 18 primary mirrors.From the picture, the photo, with 18 highlights, seems unremarkable.However, it suggests that the Webb telescope is about to complete its first phase of calibration.NASA has previously said that the Webb telescope needs to focus on the star HD84406, but how and how does that work?The Webb telescope’s primary mirror, as we all know, is made up of 18 separate sub-mirrors.Therefore, in order for these independent sub-mirrors to be accurately and completely assembled into a primary mirror for optical imaging, the Webb telescope has to undergo a series of photographic adjustments.The Webb telescope uses the near-infrared camera NIRCam to point at the primary mirror. It first confirms that the NEAR-infrared camera NIRCam is ready to collect light from the celestial body, and then identifies starlight from the same star in each of the 18 primary mirrors.First, the Webb telescope will point at HD 84406, a bright, isolated star in the constellation Ursa Major.The star was chosen because it is easy to identify and not easily disturbed by other stars of similar brightness.Each point in the composite image is labeled with the corresponding master lens number for capturing it.On February 2, 2022, the Webb Telescope began its first image capture process.It first points to the pre-calculated position of the star HD 84406.Ten detectors aligned with the primary mirror using the near-infrared camera NIRCam were generated at 156 different locations around the site, taking 10 sets of images for a total of 1560 images.The whole process took nearly 25 hours, with a whopping 54 gigabytes of raw data.Within the alignment period of 6 hours and 14 exposures, the position of the target star was determined in each sub-lens.The Webb telescope then stitched the images together to create a composite image of more than 2 billion pixels.At the center of this oversized image file are 18 images of the star HD 84406 made by the Webb Telescope’s 18 face mirrors.Next, the Webb telescope adjusts the 18 mirrors to determine which ones the bright spots correspond to.After the image matches the mirror, tilt the mirror.Form an image array according to the arrangement of mirrors.It then starts to defocus the secondary mirror of the Webb by moving it slightly, allowing the errors to be represented by a special algorithm.NASA used a phase correction algorithm to correct for errors caused by the sub-mirror.”The whole Webber team was ecstatic after making further adjustments.Because the first step of taking the image and calibrating the telescope went very well.”Marcia Rieke, a professor of astronomy and academic leader in near infrared cameras at the University of Arizona.Lee Feinberg, components manager for the Webb Optical Telescope at NASA Goddard Space Flight Center, explains the early stages of the mirror alignment process: After this adjustment, the 18 mirrors are well calibrated and can all image on their own.Next, we are going to work with these 18 face mirrors as a complete primary mirror.18 The images generated by the face mirror are superimposed, and the 18 stars converge in the center to become the intersection point.In this step, according to the program setting, the 18 slide mirrors are divided into 3 groups and overlapped in the order of grouping until they successfully intersect at a point.But so far, the debugging is not over.Each visible point in the Mosaic is imaged by one of 18 mirrors of the same star, NASA said.After the calibration of each sub-lens is determined, it is the critical first step for the Webb telescope to complete the calibration and produce scientific images.To achieve the desired assembly accuracy, NASA used dispersion fringe sensing technology to detect errors and assist in coarse sharing adjustments.The spatial frequency of dispersion fringes can reflect the magnitude of translation error, which is used as a reference for adjustment, and the shared adjustment is carried out after the initial codirection adjustment.NASA then used defocus contrast to achieve higher accuracy.After three commphases and two defocuses, the Webb telescope has preliminarily achieved its first phase goal.So with this success, the Webb telescope will officially begin its journey into deep space!Are you looking forward to the new photos?For more exciting content, check out science New Horizons