NASA's James Webb Space Telescope passes key optics tests

Astronomers can breathe a little easier. NASA has confirmed the James Webb Space Telescope has passed checks and tests verifying its optical performance following a "fine phasing" alignment on March 11th. There also aren't any critical problems or detectable blockages. Optical systems are performing "at, or above, expectations," NASA said.

The fine phasing corrected alignment errors by using optical elements inside the James Webb Space Telescope's NIRCam science instrument. The mission team gauged the performance by aligning and focusing the telescope on a star. The technology is very sensitive — as you can see above, Webb captured galaxies and stars in the background despite the very bright star in the middle.

NASA expects to finish aligning the observatory across all instruments by early May or sooner. After that, the team will spend two months prepping the instruments for capturing and sharing the first practical images and data in the summer.

The milestones show not just that Webb survived the 930,000-mile journey to its observation point, but that the telescope's novel segmented mirror design works as promised — particularly important given the $10 billion price tag, numerous delays and Hubble's mounting problems. For the most part, scientists can now concentrate on how they'll use Webb to study the early universe and other elusive aspects of the cosmos.