Each dot visible in this image mosaic from the Near Infrared Camera (NIRCam) instrument onboard the NASA/ESA/CSA James Webb Space Telescope is the same star as imaged by each of telescope’s 18 primary mirror segments.
“Launching Webb to space was of course an exciting event, but for scientists and optical engineers, this is a pinnacle moment, when light from a star is successfully making its way through the system down onto a detector,” said Webb project scientist Dr. Michael McElwain, an astronomer at NASA’s Goddard Space Flight Center.
Webb is nearing completion of the first phase of the months-long process of aligning the telescope’s primary mirror using the NIRCam instrument.
The Webb team’s challenge was twofold: (i) confirm that the camera was ready to collect light from celestial objects; and (ii) identify starlight from the same star in each of the 18 primary mirror segments. The result is an image mosaic of 18 randomly organized dots of starlight.
“The entire Webb team is ecstatic at how well the first steps of taking images and aligning the telescope are proceeding,” said NIRCam principal investigator Professor Marcia Rieke, an astronomer at the University of Arizona.
“We were so happy to see that light makes its way into NIRCam.”
During the image capturing process that began February 2, 2022, Webb was repointed to 156 different positions around the predicted location of the star and generated 1,560 images using NIRCam’s 10 detectors, amounting to 54 gigabytes of raw data.
“The initial search covered an area about the size of the full Moon because the segment dots could potentially have been that spread out on the sky,” said Webb deputy scientist Dr. Marshall Perrin, an astronomer at the Space Telescope Science Institute.
“Taking so much data right on the first day required all of Webb’s science operations and data processing systems here on Earth working smoothly with the observatory in space right from the start.”
“And we found light from all 18 segments very near the center early in that search! This is a great starting point for mirror alignment.”
Each unique dot visible in the image mosaic is the same star as imaged by each of Webb’s 18 primary mirror segments.
Moving forward, Webb’s images will only become clearer, more detail-laden, and more intricate as its other three instruments arrive at their intended cryogenic operating temperatures and begin capturing data.
The first scientific images are expected to be delivered to the world in the summer.
Though this is a big moment, confirming that Webb is a functional telescope, there is much ahead to be done in the coming months to prepare the observatory for full scientific operations using all four of its instruments.
This article is based on text provided by the National Aeronautics and Space Administration.
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