Webb Telescope reaches major milestone: All its light is in one place

Enlarge (credit: NASA/STSci)

Today, NASA shared an image indicating that the agency had successfully completed the image-alignment stage of commissioning the James Webb Space Telescope. The Webb's primary mirror is composed of 18 individual segments, and, as of today's update, all of those segments are aligned so that a single star shows up as a single object. While several more focusing steps are still required, the path to commissioning the telescope keeps getting shorter.

Immediately after launch, NASA's attention was on unfolding all the pieces of the telescope that had to be held in a compact configuration to fit inside the launch vehicle. This process included reorienting and extending the primary mirror, lowering the secondary mirror into place, and stretching out the multilayered sunscreen that helps keep the imaging hardware cold.

To the surprise and delight of many people, all that unfolding went incredibly smoothly. Since then, the focus has shifted to... well, focus. The Webb's primary mirror consists of 18 separate mirrors in a hexagonal array, each of which can be controlled separately. When the primary mirror was first unfolded, the separate mirrors reflected 18 individual smears scattered across the secondary mirror.

Read 2 remaining paragraphs | Comments