The first step in a long process of aligning the telescope’s mirrors
NASA unveiled a mosaic of the first images captured by the revolutionary James Webb Space Telescope, or JWST, today. The image represents the early stages of the telescope’s 18 main mirror segments properly aligning before JWST reaches its full potential.
The image is blurry, but this is actually a good starting point in the long process of adjusting JWST’s mirrors to take ultra-sharp photos of the distant Universe. The 18 points of light that appear in the image all represent the same isolated star, known as HD 84406, seen by a different primary mirror segment. Light collected from each primary mirror segment was reflected back to Webb’s secondary mirror, then measured using one of the telescope’s key imaging instruments, the Near Infrared Camera, or NIRCam. This sensor will be used throughout the telescope’s alignment process to determine and correct any optical errors.
The process of collecting the light used to generate the image mosaic took about 25 hours, according to NASA. The 18 images of HD 84406 were pieced together from more than 1,500 images collected as Webb was pointed to various positions around the expected location of the star. The mirror will begin to align correctly following the various adjustments that the telescope will make over the coming months. Ultimately, those 18 stars will become one as all of the mirror segments are aligned to create a seamless surface.
After quite a few delays, JWST finally launched into space on Christmas Day, ending a decades-long waiting game. But the process didn’t stop there. Just days later, the telescope started entering its final form through a complex, two-week-long unfolding sequence. On January 4th, JWST successfully deployed its giant sunshield, which is essential to keeping its instruments cold. With the successful unfurling of its primary mirror on January 8th, all major deployments were completed. On January 24th, JWST reached its final orbit in space.
NASA expects the first set of clear images for scientific observation to come in the summer. But for now, the JWST team is excited by the results of the telescope’s first imaging and alignment steps, which bring it one step closer to taking amazing images.
“Launching Webb to space was of course an exciting event, but for scientists and optical engineers, this is a pinnacle moment, when light from a star is successfully making its way through the system down onto a detector,” JWST project scientist Michael McElwain said in a blog post.
