After James Webb Space Telescope officials released an impressive 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 itself with its infrared camera (NIRCam), as the constellation showed. But the observatory still has four other instruments, of which it is able to switch with a perfect alignment to get sharp images of distant objects.
Work will begin on the lead instrument (called the Fine Guidance Sensor or FGS) and then extend to the other three instruments, a NASA update said Thursday (March 17). Webb engineers expect this process, called “multi-instrument multi-field alignment”, to take six weeks to complete.
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Webb is said to have completed its commissioning period around June, six months after launching on December 25 on an ambitious mission to observe the universe from deep space and collect data on objects, ranging from exoplanets to galaxies.
Switching between cameras in space is complicated, but the telescope will eventually be able to use several instruments at the same time, according to an update written by Jonathan Gardner, Web Assistant Senior Project Scientist at NASA’s Goddard Space Flight Center in Maryland.
Ground-based telescopes have the advantage that engineers are available on site to remove any instruments that are not needed between investigations. However, on Webb and other space telescopes, the procedure is different.
“All cameras see the sky at the same time; to switch a target from one camera to another, we turn the telescope around to set the target and 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 instruments,” while knowing the relative positions of each field of view of each instrument.
Last weekend, Gardner continued, engineers learned the positions of three near-infrared instruments in relation to the FGS, and updated this information in the software shown for the telescope.
FGS recently reached its own milestone that completed the “fine guide mode”. This happens when the guide zeroes in on a guide star at the highest possible precision of the instrument. In addition, engineers take “dark” images to see what happens when the instrument does not reach light, which allows staff to calibrate the instrument more accurately.
The last instrument to be equipped is the Middle Infrared Instrument (MIRI) because it was waiting for the ability of a cryogenic cooler to bring it to its operating temperature of minus 448 degrees Fahrenheit (minus 267 degrees Celsius).
Gardner also explained how the instruments work together to see a target.
“With parallel science exposures, when we point one instrument at a target, we can read another instrument at the same time,” he said. “The parallel observations do not see the same point in the sky, so they are what is essentially a random sample of the universe.”
Parallel data, he concluded, allow scientists to determine the statistical properties of galaxies that are recognized. In addition, for programs that want to map a large area, many of the parallel images will overlap, which will increase the efficiency of the valuable web dataset. “.
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