The first phase of the James Webb Space Telescope’s months-long process of aligning the observatory’s 18-segmented primary mirror is approaching completion.
The Near Infrared Camera (NIRCam) device was used for the alignment. The observatory focused on a single star distorted 18 times into a hexagonal form.
Webb’s 18 main mirror segments each imaged the same star as a different dot, which will eventually be aligned into a single, precise focus. However, the interim result is a star repeated perfectly in a hexagonal pattern like a magnificent heavenly snowflake.
“The result is an image mosaic of 18 randomly organized dots of starlight, the product of Webb’s unaligned mirror segments all reflecting light from the same star back at Webb’s secondary mirror and into NIRCam’s detectors,” NASA said in a blog post.
The team will gradually modify the mirror segments over the next month until the 18 pictures merge into a single star.
Webb was repointed to 156 different points around the projected location of the star throughout the image gathering procedure, which began on February 2, and 1,560 photos were obtained using NIRCam’s ten detectors.
Even though the entire operation took approximately 25 hours, the observatory was able to find the target star in each of its mirror segments within the first six hours and 16 exposures. These photos were then combined together to create a single, enormous mosaic capturing the signature of each major mirror section in a single frame.
“This 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 Marshall Perrin, deputy telescope scientist for Webb and 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.”
Webb’s photos will only get clearer, more detailed, and more complicated once its other three sensors reach their cryogenic operational temperatures and begin collecting data.
The first scientific photographs are planned to be made available to the public this summer. Until then, NASA stated that considerable work is to be done in the coming months to ready the observatory for entire scientific operations with all four of its equipment.