This coming July 12, the James Webb Space Telescope will present never-before-seen color images of the universe and the most distant galaxies, and to start getting excited, the fine guidance sensor (FGS) by Webb, developed by the Canadian Space Agency, provided a sneak peek photo.
This instrument, which is not technically the telescope’s camera, recently captured a view of stars and galaxies that provides a tantalizing glimpse of what the telescope’s science instruments will reveal in the coming weeks, months and years.
FGS has always been capable of capturing images, but its primary purpose is to enable precise scientific measurements and precision pointing imaging. When capturing images, the images are generally not saved: Given the limited communications bandwidth between L2 and Earth, Webb only sends back data from up to two science instruments at a time.
“The resulting engineering test image has some rough qualities around the edges. It was not optimized to be a scientific observation; rather, the data was taken to test how well the telescope could stay locked on a target, but hints at the power of the telescope. It carries some characteristics of the opinions that Webb has produced during its post-launch preparations. Bright stars stand out with their six long, sharply defined diffraction peaks, an effect due to Webb’s six-sided mirror segments. Beyond the stars, galaxies fill almost the entire background.
The result, using 72 exposures over 32 hours, is among the deepest images of the universe ever taken, according to Webb scientists.” POT.
“With the Webb telescope achieving better-than-expected image quality, early in the commissioning we intentionally defocused the guides by a small amount to help ensure they met their performance requirements. When this image was taken, I was thrilled to clearly see all the detailed structure in these faint galaxies. Given what we now know is possible with deep broadband guidance images, perhaps such images, taken in parallel with other observations where feasible, could prove scientifically useful in the future,” said Neil Rowlands, Program Scientist for the Webb Fine Guide Sensor, at Honeywell Aerospace.
Jane Rigby, Webb’s operations scientist at NASA Goddard Space Flight Center in Greenbelt, Maryland, noted the following:
“The faintest spots in this image are exactly the types of faint galaxies that Webb will study in its first year of science operations,” Rigby said.