Even the technical test images from the Webb telescope manage to impress

This Fine Guidance Sensor test image was captured in early May in parallel with eight days of NIRCam imaging of star HD147980.
Enlarge / This Fine Guidance Sensor test image was captured in early May in parallel with eight days of NIRCam imaging of star HD147980.

NASA, CSA and FGS team

We’re now just five days away from the public release of the first scientific images from the James Webb Space Telescope, and we’re really excited. After more than two decades and $10 billion, it’s time for Webb to pay off.

The first signs speak for it.

On Wednesday evening, NASA released a “test image” from the telescope, suggesting that the forthcoming scientific images and data will be spectacular. The release of the test photo, which NASA casually says is “among the deepest images of the universe ever taken,” almost feels like a flex because it’s so good for a disposable engineering image.

The space agency collected the image in late May during a week-long stability test designed to demonstrate the capabilities of the telescope’s fine-tuning sensor. This instrument helps Webb find and lock on to astronomical targets and was built by the Canadian Space Agency.

“The resulting technical test image has some rough edges,” NASA said in a press release. “It was not optimized for a scientific observation, rather the data was taken to test how well the telescope can remain locked on a target, but it is indicative of the telescope’s performance.” It bears some of the characteristics of the views Webb produced during post-launch preparations. Bright stars are characterized by their six long, sharply defined diffraction peaks – an effect attributed to Webb’s six-sided mirror segments. Beyond the stars, galaxies fill most of the background.”

Most of the objects in this image are not stars but distant galaxies. These are the types of galaxies astronomers love to study because they will reveal information about the early Universe. Intended for technical testing only, this image does not use color filters that allow astronomers to judge the ages of the galaxies in the image, but it does show detailed structure in distant galaxies.

Incidentally, the stability test was successful, and Webb recently collected data with all of his scientific instruments turned on and operational. We will see the fruits of this labor in just five days, starting at 10:30 am ET (14:30 UTC).