The James Webb Space Telescope has taken its first image of a star. In fact, it’s taken 18 of them, as the images were captured as part of the months-long process of precisely aligning the 18 segments that make up the telescope’s mirror.
The star that was imaged, HD84406, was selected because it’s so easily identifiable – there are no other stars of a similar brightness in its vicinity. Webb then observed the star using its Near Infrared Camera (NIRCam), which has a wide field of view, making it easier to find the star in each segment of the mirror.
Using 1,560 images taken with the NIRCam over 25 hours, the Webb team was able to identify the star in all 18 mirror segments.
“This initial search covered an area about the size of the full Moon because the segment dots could potentially have been that spread out on the sky,” said Dr Marshall Perrin, Deputy Telescope Scientist for Webb. “We found light from all 18 segments very near the centre early in that search. This is a great starting point for mirror alignment.”