James Webb Space Telescope captures its first images of a star
The James Webb Space Telescope has finally captured its first image of a star — or rather, images. NASA has shared a mosaic of pictures (shown above) of a star taken using the primary mirror's 18 segments. It looks like a seemingly random collection of blurry dots, but that's precisely what the mission team was expecting. The imagery will help scientists finish the lengthy mirror alignment process using the telescope's Near Infrared Camera, or NIRCam. The first phase is nearly complete as of this writing.
The visuals came from a 25-hour effort that pointed the James Webb Space Telescope to 156 different positions and produced 1,560 images with the NIRCam's sensors. The team created the mosaic using the signature of each mirror segment in a single frame. Visual artifacts come from using the infrared camera at temperatures well above the frigid conditions the telescope will need for scientific observation. And what you see here isn't the entirety of the mosaic — the full-resolution snapshot is over two gigapixels.
NASA also provided a rare real-world glimpse at the JWST in action. The agency provided a "selfie" of the primary mirror (middle) created by a pupil imaging lens from the NIRCam. This too is blurry, but it offers a valuable look at the fully deployed mirror and helps explain the importance of alignment. Notice how just one segment is brightly lit by a star? It's the only one aligned with that celestial body — it will take a while before all segments are operating in concert.
Researchers expect the first scientifically useful images from JWST in the summer. It's reasonable to presume those pictures will be considerably more exciting, especially as they start providing glimpses of the early universe. Still, what you see here demonstrates the telescope's health and suggests there won't be much trouble in the months ahead.