Following the completion of mirror alignment steps, the Webb team expects that the telescope’s optical performance will be able to meet or exceed its science goals.
While the purpose of this image was to focus on the bright star at the center for alignment evaluation, Webb’s optics and NIRCam are so sensitive that the galaxies and stars seen in the background show up. At this stage of Webb’s mirror alignment, known as fine phasing, each of the primary mirror segments have been adjusted to produce one unified image of the same star using only the NIRCam instrument. This image of a star called 2MASS J17554042+6551277 uses a red filter to optimize visual contrast. Image credit: NASA / STScI.
On March 11, 2022, members of the Webb team completed the stage of alignment known as fine phasing.
At this key stage in the commissioning of Webb’s Optical Telescope Element, every optical parameter that has been checked and tested is performing at, or above, expectations.
The team also found no critical issues and no measurable contamination or blockages to Webb’s optical path.
The telescope is able to successfully gather light from distant objects and deliver it to its instruments without issue.
Although there are months to go before Webb ultimately delivers its new view of the cosmos, achieving this milestone means the team is confident that Webb’s first-of-its-kind optical system is working as well as possible.
“More than 20 years ago, we set out to build the most powerful telescope that anyone has ever put in space and came up with an audacious optical design to meet demanding science goals,” said Dr. Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate.
“Today we can say that design is going to deliver.”
While some of the largest ground-based telescopes on Earth use segmented primary mirrors, Webb is the first telescope in space to use such a design.
The 6.5-m (23.1-foot) primary mirror is made up of 18 hexagonal, beryllium mirror segments.
It had to be folded up for launch and then unfolded in space before each mirror was adjusted to form a single mirror surface.
“In addition to enabling the incredible science that Webb will achieve, the teams that designed, built, tested, launched, and now operate this observatory have pioneered a new way to build space telescopes,” said Webb optical telescope element manager Lee Feinberg, a researcher at NASA’s Goddard Space Flight Center.
With the fine phasing stage of the telescope’s alignment complete, the Webb team has now fully aligned the telescope’s Near-Infrared Camera (NIRCam) to its mirrors.
“We have fully aligned and focused the telescope on a star, and the performance is beating specifications,” said Webb deputy optical telescope element manager Ritva Keski-Kuha, also from NASA’s Goddard Space Flight Center.
“We are excited about what this means for science.”
“We now know we have built the right telescope.”
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This article is based on text provided by the National Aeronautics and Space Administration.
Source link: https://www.sci.news/astronomy/webbs-optics-10626.html
