NASA’s James Webb Space Telescope alignment completed

Credit: NASA’s Goddard Space Flight Center

NASA Web fully focused and ready to power devices

revenge[{” attribute=””>NASA’s Webb Space Telescope Image Sharpness Test

Webb Space Telescope Image Sharpness Test. Credit: NASA/STScI

The alignment of the telescope across all of Webb’s instruments can be seen in a series of images that captures the observatory’s full field of view.

“These remarkable test images from a successfully aligned telescope demonstrate what people across countries and continents can achieve when there is a bold scientific vision to explore the universe,” said Lee Feinberg, Webb optical telescope element manager at NASA’s Goddard Space Flight Center.


The Webb Telescope completes the alignment phase. Credit: NASA’s Goddard Space Flight Center

The telescope’s optical performance is still better than the engineering team’s most optimistic predictions. Webb’s mirrors now direct the fully focused light collected from space into each instrument, and each instrument successfully captures images with its supplied light. The image quality provided for all instruments is ‘limited diffraction’, which means that the resolution of the detail that can be seen is as good as physically possible given the size of the telescope. From this point on, the only changes to the mirrors will be very small periodic adjustments to the primary mirror sections.

“With the telescope alignment and half-life efforts, my role on the James Webb Space Telescope mission is over,” said Scott Acton, Ball Aerospace Wavefront Detection and Control Scientist. “These images have profoundly changed the way I see the universe. We are surrounded by a symphony of creation. There are galaxies everywhere! I hope everyone in the world can see them.”

Web telescope image sharpness test

Geometric images of highly focused stars in each instrument’s field of view show that the telescope is perfectly aligned and in focus. In this test, Webb pointed to a portion of the Large Magellanic Cloud, a satellite galaxy of the Milky Way, providing a dense field of hundreds of thousands of stars across all of the observatory’s sensors. The image sizes and positions shown here show the relative arrangement of both Webb’s instruments in the telescope’s focal plane, with each pointing toward a slightly parallel portion of the sky relative to the other. Webb’s three imaging tools are NIRCam (image shown here at a wavelength of 2 μm), NIRISS (image shown here at 1.5 μm), and MIRI (image shown here at 7.7 μm, the longest wavelength. The length that detects emissions from interstellar clouds such as as well as starlight). NIRSpec is a spectrophotometer, not an imager, but it can capture images, like the 1.1 µm image shown here, for calibration and target acquisition. The dark areas visible in parts of the NIRSpec data are due to micro-shutter matrix structures, which contain hundreds of thousands of controllable shutters that can be opened or closed to determine which light is being sent to the spectrometer. Finally, Webb’s precise orientation sensor directs the stars to orient the observatory with precision and accuracy; Its two sensors are not usually used for scientific imaging, but they can take calibrated images like the ones shown here. This image data is used not only to assess image sharpness, but also to measure and calibrate fine image distortions and alignment between sensors as part of the overall Webb Tool calibration process. Credit: NASA/STScI

Now, Webb’s team will turn its attention to commissioning the scientific instrumentation. Each device is a highly advanced set of detectors equipped with lenses, masks, filters and customized equipment that helps them do the science they are designed for. The specialized properties of these tools will be configured and run in different combinations during the tool run phase to fully confirm their readiness for science. With the formal completion of the telescope alignment, key personnel involved in operating each instrument have arrived at the mission operations center at the Space Telescope Science Institute in Baltimore, and some personnel involved in telescope alignment have finished their duties.

Although the telescope alignment is complete, some telescope calibration activities remain: As part of the flag instrument operation, the telescope will be directed to point to different regions of the sky where the total amount of solar radiation arriving at the observatory varies to confirm thermal stability at the changing target. In addition, continuous maintenance observations every two days will monitor mirror alignment and, when necessary, apply corrections to keep mirrors in their aligned positions.

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