James Webb Telescope just took a selfie of its giant golden mirrors?
NASA has released a selfie taken by the James Webb Space Telescope (JWST) as it attempts to align its 18 giant mirrors to capture light from the earliest stars and galaxies. The process is expected to take several months to complete and the telescope is likely to begin capturing scientific images only by the summer of 2022.
Launched on Christmas Day last year, the JWST has completed its journey of a million miles, away from the Earth and now reached its vantage point to peer into the universe's past. The team of researchers has been working throughout this time to ensure that a million things that could possibly go wrong with the telescope do not come to pass.
NASA recently released the first image of a star from the telescope. The mosaic image consists of starlight from a single star, HD84406, as reflected individually by the 18 unaligned mirrors onto the secondary mirror of the telescope and then captured by the Near Infrared Camera (NIRCam).
One of the four major instruments on the JWST, the NIRCam is the telescope's wavefront sensor that will be used to sense and correct issues in the optics of the telescope. Using wavefront sensing, JWST can ensure that its 18 giant mirrors work in sync as one giant mirror and do not create any artifacts.
According to NASA's post, it was also selected to be used in the mirror alignment steps since it has a wide field of view and the capability to operate at higher temperatures. To fulfill its role in aligning the mirrors, the NIRCam also received a custom set of components, such as a specialized pupil imaging lens.
The specialized lens has no role in capturing scientific images in the future but has only been installed to help in the alignment process. By taking selfies of the mirror segments, the lens provides important information on their alignment and will be used to complete the alignment process.
NASA has warned that since the NIRCam is operating at temperatures higher than the cryogenic temperatures it is designed to work under, it will throw up artifacts in preliminary images. Along with other instruments that will kick in when they reach their ideal operating temperatures, the NIRCam will capture more accurate data.
According to the JWST website, the NIRCam is also equipped with coronagraphs, a piece of equipment that allows the capture of faint objects near brighter ones. When used, the coronagraphs will dim the lights from the brighter object, just like a raised hand dims the light from the sun. The ability to view dimmer objects will help the NIRCam spot and investigate planets orbiting near other stars.
The James Webb Space Telescope is just getting started.
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