NASA's work to align the James Webb Space Telescope is extending to more instruments

An image taken by the James Webb Space Telescope during its alignment process shows galaxies and stars in the background.
An image taken by the James Webb Space Telescope during its alignment process shows galaxies and stars in the background. (Image credit: NASA/STScI)

After James Webb Space Telescope officials released a stunning image of a single star, the team is ready to get other telescope parts in line with the observatory's mirrors.

The $10 billion telescope successfully aligned with its near-infrared camera (NIRCam), as the star image showed. But the observatory still has four other instruments that it must be able to switch between with perfect alignment to obtain sharp images of distant objects.

The work will begin with the guiding instrument (called the Fine Guidance Sensor or FGS) and then extend to the other three instruments, a NASA update stated Thursday (March 17). Webb engineers expect that this process, called "multi-instrument multi-field alignment," will take six weeks to complete.

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Webb should complete its commissioning period around June, six months after launching on Dec. 25 on an ambitious mission to observe the universe from deep space and gather data on objects ranging from exoplanets to galaxies.

Switching between cameras in space is complicated, but the telescope will eventually be able to use multiple instruments at the same time, according to the update, which was written by Jonathan Gardner, Webb deputy senior project scientist at NASA's Goddard Space Flight Center in Maryland.

Ground-based telescopes have the advantage of having engineers available on site to potentially remove instruments not needed in between investigations. However, on Webb and other space telescopes, the procedure is different.

"All the cameras see the sky at the same time; to switch a target from one camera to another, we repoint the telescope to put the target into the field of view of the other instrument," Gardner wrote.

The goal of the new alignment, Gardner said, is to "provide a good focus and sharp images in all the instruments" while knowing the relative positions of each instrument's field of view.

The James Webb Space Telescope after separating from the Ariane 5 rocket that carried it into space. This is one of our last views of the impressive telescope.  (Image credit: ESA)

Last weekend, Gardner continued, engineers learned the positions of three near-infrared instruments in relation to the FGS, and updated that information in the software used for telescope pointing.

FGS reached its own milestone recently, which was finishing "fine guide mode." That occurs when the guider zeroes in on a guide star to the instrument's highest possible precision. Additionally, engineers are taking "dark" images to see what happens when the instrument has no light reaching it, which allows personnel to more precisely calibrate the instrument.

The last instrument to be aligned will be the mid-infrared instrument (MIRI) as it is awaiting a cryogenic cooler's ability to bring it to its operating temperature of minus 448 degrees Fahrenheit (minus 267 degrees Celsius.)

This gif shows the "before" and "after" images from Segment Alignment, when the team corrected large positioning errors of its primary mirror segments and updated the alignment of the secondary mirror. (Image credit: NASA/STScI)

Gardner also explained how the instruments will work together to look at a target.

"With parallel science exposures, when we point one instrument at a target, we can read out another instrument at the same time," he said. "The parallel observations don't see the same point in the sky, so they provide what is essentially a random sample of the universe." 

Parallel data, he concluded, allows scientists to "determine the statistical properties of the galaxies that are detected. In addition, for programs that want to map a large area, much of the parallel images will overlap, increasing the efficiency of the valuable Webb dataset."

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Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: