NASA’s scientists behind the James Webb Space Telescope have shown off the first glimpse into the overwhelming power of images it will produce, saying that what we see is a preview of the test run.
The calibration test image that was composited together from 32 hours and 72 exposures, “is among the deepest images of the universe ever taken” and the telescope is only getting started, NASA notes on its website.
Almost as fabulous as the image itself is the fact that this photo was taken as part of an early test of the telescope’s Fine Guidance Sensor (FGS). Its task is to make sure the cameras and mirrors are all aligned correctly.
FGS has always been capable of capturing imagery, but its primary purpose is to enable accurate science measurements and imaging with precision pointing, but the imagery is typically not kept given the limited communications bandwidth between L2 and Earth.
When FGS’ aperture is open, it is not using color filters like the other science instruments, meaning it is impossible to study the age of the galaxies in this image with the rigor needed for scientific analysis. However, even when capturing unplanned imagery during a test, FGS is capable of producing stunning views of the cosmos.
With its designed observatory capability in finding and locking onto its targets, Webb’s Fine Guidance Sensor (FGS) captured a view of stars and galaxies that provides a tantalizing glimpse at what the telescope’s science instruments will reveal in the coming weeks, months, and years.
Neil Rowlands, program scientist for Webb’s (FGS) at Honeywell Aerospace said,” With the Webb telescope achieving better-than-expected image quality, early in commissioning we intentionally defocused the guiders by a small amount to help ensure they met their performance requirements.”
“I was thrilled to clearly see all the detailed structure in these faint galaxies when this image was taken,” Neil Rowlands said. “Perhaps such images, taken in parallel with other observations where feasible, could prove scientifically useful in the future.”
NASA’s James Webb Telescope Imagery
Because this image was not created with a scientific result in mind, there are a few features that are pretty different from the full-resolution images that will be released on July 12th. Those images will include what will be for a short time at least the deepest image of the universe ever captured, as NASA Administrator Bill Nelson announced on June 29th.
The FGS image is colored using the same reddish color scheme that has been applied to Webb’s other engineering images throughout commissioning, and there was no “dithering” during these exposures.
In addition, the centers of bright stars appear black because they saturate Webb’s detectors, and the pointing of the telescope didn’t change over the exposures to capture the center from different pixels within the camera’s detectors. The overlapping frames of the different exposures can also be seen at the image’s edges and corners.
The purpose of this engineering test was to lock onto one star and to test how well Webb could control its “roll”—literally, Webb’s ability to roll to one side like an aircraft in flight.
Jane Rigby, Webb’s operations scientist, said, “The test was performed successfully—in addition to producing an image that sparks the imagination of scientists who will be [analyzing] Webb’s science data.”
NASA said it is less than one week away from the release of the first full-color images from NASA’s James Webb Space Telescope. Until then, we are anxiously waiting to see how the telescope, two decades in the making, can outdo itself.