The Webb Space Telescope has just passed another milestone. On Wednesday, March 16, NASA officials announced that the primary mirror is now fully aligned. The mirror in question has a width of 6.5 m and is made up of 18 hexagonal segments. Before scientific observations can begin, all of these elements need to line up and work as a single mirror.
Thus, the alignment process, which involves adjustments down to the nanometer, is now complete. To mark the event, NASA released the first image recorded by the telescope after the alignment, and agency scientists were quick to express their amazement at the quality of the images captured by Webb.
According to Jane Rigby, a scientist at NASA’s Goddard Space Flight Center and a member of Webb’s team, the telescope’s performance matches “everything they had dared to hope for”.
Very promising results
To proceed with the alignment of the 18 elements of the main mirror, the NASA researchers pointed the telescope towards the star called HD 84406. This one is described as being a “very boring star” by the scientists, it is 100 times fainter than what can be seen with the naked eye. However, this star was chosen for its level of luminosity and its location.
At the start of the alignment, the telescope produced 18 images of the same star, with each segment producing its own image. However, the image just released shows a single bright, amber-colored star with beams of light radiating from the center. But what’s even more interesting is the fact that the background shows dozens of little bright spots that are actually distant galaxies that you couldn’t see before. With these galaxies, this first image taken by Webb can be called a deep field. This kind of image aims to capture the most distant objects in the Universe.
The Hubble telescope is a specialist in deep fields. However, Webb was designed to be even more powerful than Hubble in this area. The main difference between the two telescopes is that Hubble captures visible light and ultraviolet radiation. As for Webb, he can only pick up infrared radiation.
According to NASA scientists, Webb was developed to be up to 100 times more sensitive than Hubble. With this first image, it seems that this objective has been achieved, even exceeded.
What remains to be done
After aligning the main mirror, Webb’s team will now focus on the telescope’s 4 science instruments. The NIRCam or Near Infrared Camera instrument has already been used to accomplish mirror alignment. The other three are still waiting to be activated.
Apart from the alignment, it is still necessary to wait for the instruments to cool down to extremely low temperatures close to absolute zero. Any source of heat would indeed risk creating interference at the level of the detectors and preventing them from seeing the most distant objects in the Universe.
The results of the first scientific observations made by Webb are expected to arrive in June or July. For the moment, NASA has not indicated what will be the first target of the new telescope.