NASA releases stunning images from James Webb Space Telescope in final stage of testing

31 May 2022

"Better than our most optimistic prediction" – first images from James Webb exceed all expectations

Having completed the self-assembly of its 18-segmented main mirror, the telescope has now taken exceptional images of an unexceptional star as a test of its capabilities. The star, known as HD84406, is 100 times fainter than what can be seen with the human eye. The star itself is of little interest, lovely though its image is – instead, astronomers are captivated by the spray of tiny dots scattered across the background. Each is a distant galaxy, and this is the first time we’ve ever been able to capture them.
In a virtual briefing, NASA officials expressed their overwhelming joy and relief at what these first images represent.

These first images are not scientific – instead, they’re engineering images, designed to test how smoothly all the many parts of this engineering marvel are working together. The $US10 billion dollar telescope is staggeringly complex in design, and the stakes are high – where the Hubble telescope orbits the Earth, within our reach to service, James Webb sits approximately 3000 times further away, orbiting the Sun. While this extends our view of deep space phenomenally, it also means that we have no option to make adjustments or repairs if something goes awry.
The pressure to ensure each and every component of the telescope was perfect before launching it into space was enormous, and led to a number of delays.
(This new “selfie” was created using a specialized pupil imaging lens inside of the NIRCam instrument that was designed to take images of the primary mirror segments instead of images of the sky. This configuration is not used during scientific operations and is used strictly for engineering and alignment purposes. In this image, all of Webb’s 18 primary mirror segments are shown collecting light from the same star in unison. Credit: STScI / NASA
But since its launch in December 2021, every stage of deployment has progressed flawlessly.
The telescope’s main mirror is 6.5 meters wide and composed of 18 hexagonal segments that are self-assembled in space. The alignment of each of these segments to complete a single, smooth reflecting surface requires nanometer-scale precision. Until now, there has been no way to confirm how well the process has unfolded, and the wait for these first images has been a nervous one. The relief that accompanies this stellar portrait is almost tangible.)

More than just confirming that the telescope is operating smoothly, these first images are also a clear demonstration of James Webb’s capabilities.
One hundred times more sensitive than Hubble, and operating in the realm of infrared, James Webb is already capturing galaxies far more distant than any we have before.

The latest image from the James Webb Space Telescope shows an amazing view of the Large Magellanic Cloud, a satellite galaxy of the Milky Way.
The image was captured with JWST's coldest instrument: the Mid-Infrared Instrument, or MIRI.
Focussing on the star field of the Large Magellanic Cloud provides an opportunity for Webb scientists to test the telescope's imaging performance.
credit:- NASA

JWST's 18-star mosaic

The JWST team released an image in February 2022 showing 18 ‘different’ stars scattered across a black background.
In fact, the image - seen below - showed a single bright star in the constellation Ursa Major known as HD 84406.
A mosaic of the same star captured 18 times captured by James Webb Space Telescope. This image was used by NASA scientists to align JWST's primary mirror. Credit:- NASA
The star was seen in 18 different positions because JWST’s mirror segments were still in the process of being aligned.

“There’s no way that Webb can look for 2,000 seconds at any point in the sky, and not get an incredibly deep field,” Rigby says. “This is going to be the future from now on. Wherever we look, it’s a deep field. Without even really breaking a sweat, we’re seeing back in time to galaxies that we’re seeing the light as it looked billions of years ago.”
And the process has only just begun.

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