Less than a week to go until July 12, 2022, the release of the first quality science images from NASA James Webb . Space Telescope, but how does the observatory find and lock its target? Webb’s sophisticated Guide Sensor (FGS), developed by the Canadian Space Agency, was designed with this specific question in mind. It recently captured a view of stars and galaxies, providing a fascinating glimpse into what the telescope’s scientific instruments will reveal in the coming weeks, months and years. .
Image credits: NASA, CSA and the FGS . team
FGS has always been capable of capturing images, but its main purpose is to enable precise scientific measurements and images with precise orientation. When it captures the image, it is usually not preserved: due to the limited communication bandwidth between L2 and Earth, Webb only sends data from up to two scientific instruments at a time. But during a week-long stability test in May, the team realized they could retain the image being captured because of the available data transmission bandwidth.
The engineering test image – created during thermal stability testing in mid-May – has some rudimentary qualities to it. It’s not optimized to be a scientific observation, the data is instead taken to test how well the telescope can keep on target, but it does hint at the telescope’s power. Astronomy. It carries some of the standout features of the perspective that Webb created during its post-launch preparation. The bright stars are distinguished by six long, well-defined diffraction spikes – an effect due to Webb’s hexagonal mirror segments. In addition to stars – galaxies fill almost the entire background.
The result – using 72 exposures over 32 hours – is one of the deepest images of the universe ever taken, according to Webb scientists. When the FGS aperture is open, it doesn’t use a color filter like other scientific tools – which means it’s not possible to study the ages of the galaxies in this image with the rigor needed for scientific analysis. But: Even when taking unplanned images during the test, the FGS was able to create a beautiful view of the universe.
In this image, the acquired FGS image parallels the NIRCam image of the star HD147980 over a period of 8 days in early May. This image shows a 32-hour exposure at several points of Guider 2 channel overlap. Observations are not optimized to detect faint objects, but nevertheless, the image captures objects. extremely faint and currently the deepest image of the infrared sky. The guider’s unfiltered wavelength response, from 0.6 to 5 micrometers, helps provide this extreme sensitivity. Images are monochrome and rendered in pseudo-color with white-yellow-orange-red showing the progression from lightest to dimmest. The bright star (at 9.3 magnitude) at the right edge is 2MASS 16235798 + 2826079. There are only a handful of stars in this image – distinguished by their diffraction spikes. The rest of the objects are thousands of faint galaxies, some in the nearby universe, but many others in the high redshift universe.
Source: NASA
