Recently, the James Webb Space Telescope successfully took and transmitted back the first set of stellar photos and the first "selfie".
The first set of stellar photographs showed starlight from the same star captured by the 18 main mirrors of the Weber telescope, while the Webb telescope successfully completed the first "selfie" using a dedicated pupil imaging lens inside the near-infrared camera.
The first main mirror of the Webb telescope is "selfie", picture from NASA
Since Feb. 2, when the Webb team used a near-infrared camera (NIRCam) to calibrate the main mirror of the Weber telescope, the entire work will take several months, and the first phase of work is now nearing completion.
In the first phase of its work, the team targeted the first observations at a star, HD 84406, in the constellation Ursa Major. This star was chosen because it is easy to identify and there are fewer bright stars around it, which helps reduce visual confusion.
To test and calibrate the primary mirror, 10 detectors of the Weber NIR camera took a total of 1560 photos, obtaining 54G raw data, a process that lasted 25 hours. In the first 6 hours and 16 exposures, the team captured the starlight of the target star in all 18 mirrors of the Webb telescope. The images are then stitched together to form a giant image of more than 2 billion pixels, and the picture presented in this article is only the central part of this huge image.
The Weber telescope captured a stitched image of 18 stars, from NASA
Because the Weber telescope uses an unaligned mirror, different primary mirrors obtain different star point positions, resulting in a stitched image of 18 star points. Each unique point of light in the image is the same star captured by 18 main mirrors, which is the key to optics experts and engineers calibrating the entire Weber telescope. These images help deploy the calibration position of each specular surface and are a critical step in the calibration of the Weber telescope before scientific observations.
Over the next month or so, Webb's team will gradually adjust the mirror until the 18 dots coincide to form an image of a complete star.
Demonstration of a unified imaging process of 18 dots coinciding to form a complete star, based on NASA
The entire Weber team was ecstatic about the image shooting, and the progress of the first step in calibrating the telescope. We're excited to see light get into near-infrared cameras. Marcia Rieke, professor of astronomy at the University of Arizona and principal investigator of near-infrared cameras, said.
The near-infrared camera is the wavefront sensor and key imager of the Weber telescope. Due to the nir-infrared camera's wide field of view and ability to operate safely at higher temperatures than other instruments, it will be used for specular calibration of almost the entire Weber telescope. However, since the operating temperature of the near-infrared camera is much higher than the ideal temperature when capturing the image, the resulting image is presented in the form of a mosaic. As the Weber telescope works close to the ideal low temperature, the degree of mosaic of the image will be significantly reduced.
"Launching Weber into space is certainly an exciting event, but for scientists and optical engineers, it's the peak moment when light from a star successfully passes through the system into the probe." Michael McElwain, a scientist at the Webb telescope, said.
Looking to the future, as a functional space telescope, the image of the Weber telescope will be clearer, more detailed and more accurate. At present, the telescope's other three instruments have reached the expected low temperature operating temperature and begun to capture data, and the first scientific space images from the Weber telescope are expected to "debut" to the world in the summer of 2022.
James Webb Space Telescope Captures First Set of Stellar Photos with "Selfie" Narration, Video from NASA (03:00)