May 25, 2022

The US space agency Nasa, which leads the Webb project, released a set of engineering pictures on Thursday.

They’re not intended to be exciting; they’re merely a demonstration that all the hardware is working as it should.

The images show slightly different views of the Large Magellanic Cloud, a small satellite galaxy of our Milky Way.

In view are the points of light made by hundreds of thousands of stars.

The sizes and positions of the images depict the relative arrangement of each of Webb’s instruments as they pick up the light coming from the telescope’s golden mirrors, including from its 6.5m-wide primary reflector.

Nasa had previously released a sample of this type of imagery for the NIRCam instrument. NIRCam, which is Webb’s main camera system, was used to do the initial focusing of the observatory’s optics. When that job was complete, engineers had to work through each of the other three instruments (NIRSpec, MIRI and FGS/NIRISS) to confirm that NIRCam’s alignment worked just as well for them.

The last instrument to go through this process was MIRI, the Mid-Infrared Instrument whose development was led in part from the UK.

There will be elation today across a host of contributing British institutions to see MIRI’s first published image.

If the picture looks slightly fluffy compared with those from the other instruments, it’s because MIRI works at longer infrared wavelengths. The puffiness that surrounds the stars is the glow from carbon-rich (organic) molecules in the Large Magellanic Cloud. MIRI’s particular sensitivity allows it to tease out different features in the field of view from its instrument counterparts.

Scientists intend to use Webb and its remarkable 6.5m-wide mirror to capture events that occurred just a couple of hundred million years after the Big Bang. They want to see the very first stars to light up the Universe.

Full Article