An engineering image obtained while testing one of the instruments of the James Webb Space Telescope reveals hundreds of distant galaxies in the deepest ever glimpse into the infrared universe.
The image, released by NASA on Wednesday (July 6), was captured by the James Webb Space Telescope‘s Fine Guidance Sensor (FGS) over an eight-day period in May and includes 72 snapshots taken during a 32-hour exposure. In particular, the FGS, which was built by the Canadian Space Agency, is not a scientific instrument and instead keeps the observatory well-focused on its target.
Still, the stunning image gives a taste of what’s to come when the most powerful and expensive space observatory ever built finally begins its ambitious scientific work in earnest. The telescope is completing commissioning and the Webb team will unveil the first truly scientific images at 10:30 a.m. EDT (1530 GMT) Wednesday (July 12) during a broadcast you can watch live here on Space.com.
Live updates† NASA’s James Webb Space Telescope Mission
Related† How the James Webb Space Telescope Works in Photos
FGS took the false-color image during a “roll” test, according to a NASA pronunciation (opens in new tab) about the image. As Webb’s near-infrared camera focused on a star called HD147980, the telescope rolled back and forth like an airplane. During the test, the FGS kept the telescope pointed at its target. The resulting image, a byproduct of this supporting work, reveals the cosmos in a color scale from white to red, with whiter hues representing objects emitting the brightest infrared light and redder hues revealing fainter objects.
A handfull stars appear in the image, marked by the diffraction peaks making them look like a plus sign. The rest is galaxies†
“The faintest blobs in this image are exactly the types of faint galaxies that Webb will study in the first year of scientific operations,” Jane Rigby, Webb’s operations scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in the statement.
The image is not perfect, as it shows signs of what is known as the dithering effect, which leaves black dots in the center of the stars depicted. Dithering occurs when the telescope slightly adjusts its position between exposures, resulting in saturation of the detectors.
The primary purpose of FGS is not to create scientific images, NASA said in the statement, and most of its images will be discarded shortly after acquisition. The instrument’s job is to enable accurate measurements by other instruments by helping the telescope point precisely to the stars and galaxies the scientists are interested in. Still, the images hint at the groundbreaking discoveries to come from the observatory.
“When this image was taken, I was excited to see clearly all the detailed structures in these fuzzy galaxies,” Neil Rowlands, an FGS program scientist at Honeywell Aerospace, who built the instrument, said in the statement.
Because FGS wasn’t primarily designed to do science, it doesn’t use color filters like the other scientific instruments, meaning scientists can’t accurately determine the age of the galaxies in this image, the statement said.
While the image may be the deepest of the infrared universe ever seen by the public, its glory won’t last long as, according to NASA administrator Bill Nelson, the July 12 release will feature the deepest view of the universe ever caught.
The James Webb Space Telescope carries two cameras and two spectrometers, which record the light spectra of the imaged objects and reveal their chemical composition. The telescope is specifically designed to see infrared light to detect some of the most distant (and oldest) galaxies in the universe. Although these galaxies emit visible light, because of the redshift effect caused by the expansion of the universe, this visible light shifts to the longer infrared wavelengths, which require an ultra-cold telescope like Webb.
Follow Tereza Pultarova on Twitter @TerezaPultarova† follow us on Twitter @Spacedotcom and further facebook†
#James #Webb #Space #Telescope #test #image #shows #deepest #field #sparkling #galaxies