But the JWST has 18 mirrors!
These had to be aligned extremely precisely to capture the image NASA released today.
This gif shows several intermediary images of stars used for the crucial JWST mirror alignment process.
Its so big that none of our rockets can carry it when fully extended.
The telescope uses segmented mirror technology.
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This process began in January.
The JWST has now completed thisalignment process, giving us the first unified image.
The image was taken using thenear infrared camera (NIRCam), one of the telescopesfour key science instruments.
The NIRCam is the optical system that captures images on the James Webb Space Telescope.
Image: NASA
But how was this done?
There are sevensmall motorsfixed behind each of the JWSTs 18 slightly curved hexagonal mirrors.
Six of these motors are grouped in pairs, equally distanced, and located around each mirror segment.
These are used to move the mirror.
The seventh motor is at the center and is connected to the mirrors six corners with struts.
This motor can adjust the tension of the struts to optimize the curvature of that mirror segment.
However, there were still minute alignment errors that needed to be corrected to obtain the best possible image.
This is where the fine alignment happens.
In this process, rather than moving the mirror segments, the small optics inside NIRCam are moved instead.
The image released by NASA this week shows how a star looks when these steps are completed.
Prior to this, NASA released a stacked image (likely of the same star) back in February.
The 18 images were then stacked to produce the image below.
NASA scientists stacked the 18 individual images captured by the primary mirror segments to create a stacked image.
After this, the instrument commissioning phase will start.
Apart from NIRCam, there are three other instruments on board the JWST:NIRSpec,NIRISS, andMIRI.
All the instruments will be brought to their working temperatures and tested.
Some initial steps have already begun and all indications so far are good.
you’re free to keep up to date with the JWSTs activitiesonline.
