A month after its launch, the European space telescope Euclid, soon in position 1.5 million kilometers from Earth, opened its eye to take its first shots. Test images whose publication is a great relief for the teams of the European Space Agency (ESA) mission, who have been working on this project for more than a decade. Indeed, everything indicates that the two instruments of the telescope designed to unlock the secrets of dark matter and dark energy, a visible light imager (VIS) and a near infrared spectro-imager (NISP), are working perfectly.
Even better, the high quality of these first images, produced with minimal system tuning, suggests that the space telescope will meet or even exceed expectations in both visible and near infrared. It should therefore be able to accomplish its scientific mission of producing the largest and most accurate 3D map of the Universe ever created; all by measuring the shape, position and distance of galaxies up to 10 billion light-years away, over a third of the sky.
On the left, the first image of VIS testifies to the performance of the 36 CCD detectors with which this instrument is equipped. Together, they make it possible to photograph, in a single shot, an area of ??the sky as large as three times the full moon. As for the zoom on the right, it shows in close-up the view recorded by only one of these sensors.
On the left again, we discover the first image of NISP, taken in its direct imaging mode, which covers a roughly equivalent area of ??the sky with its 16 infrared detectors, the frame on the right showing the image from a single them in higher resolution.
Although these two images, taken with an exposure time of only 665 seconds, are still blurred by interference and other artifacts, for example the trails left by cosmic rays passing through the detector, there are already very clearly visible galaxies and stars. However, Euclid still has a long way to go to be able to begin its investigation of the dark components of our Universe: a few commissioning stages followed by a phase of verification of its performance in condition, in its new cold environment bathed in radiation. This should last about eight weeks. Only then will his quest begin, which should, if all goes well, last at least six years.