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posted by Fnord666 on Tuesday February 11 2020, @11:56AM   Printer-friendly
from the nothing-quite-like-first-light dept.

Arthur T Knackerbracket has found the following story:

The tension was high: In front of a large screen at the house near Madrid where members of the Consortium participating in the commissioning of the satellite live, as well as at the other institutes involved in CHEOPS, the team waited for the first images from the space telescope. "The first images that were about to appear on the screen were crucial for us to be able to determine if the telescope's optics had survived the rocket launch in good shape," explains Willy Benz, Professor of Astrophysics at the University of Bern and Principal Investigator of the CHEOPS mission. "When the first images of a field of stars appeared on the screen, it was immediately clear to everyone that we did indeed have a working telescope," says Benz happily. Now the remaining question is how well it is working.

Preliminary analysis has shown that the images from CHEOPS are even better than expected. However, better for CHEOPS does not mean sharper as the telescope has been deliberately defocused. This is because spreading the light over many pixels ensures that the spacecraft's jitter and the pixel-to-pixel variations are smoothed out, allowing for better photometric precision.

"The good news is that the actual blurred images received are smoother and more symmetrical than what we expected from measurements performed in the laboratory," says Benz. High precision is necessary for CHEOPS to observe small changes in the brightness of stars outside our solar system caused by the transit of an exoplanet in front of the star. Since these changes in brightness are proportional to the surface of the transit planet, CHEOPS will be able to measure the size of the planets. "These initial promising analyses are a great relief and also a boost for the team," continues Benz.

How well CHEOPS is working will be tested further over the next two months. "We will analyze many more images in detail to determine the exact level of accuracy that can be achieved by CHEOPS in the different aspects of the science program," says David Ehrenreich, CHEOPS project scientist at the University of Geneva. "The results so far bode well," said Ehrenreich.


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  • (Score: 2, Informative) by Anonymous Coward on Tuesday February 11 2020, @03:26PM (1 child)

    by Anonymous Coward on Tuesday February 11 2020, @03:26PM (#956862)

    They do not intend to undo the blur. It is there by design. They are not looking for high spatial frequency information, they are looking for photometric changes over long observational times. The expected noise from a spot moving back and forth over multiple pixels due to spacecraft jitter is larger than smearing the signal over a larger number of pixels and having the intensity distribution change a bit, but to largely stay on the same pixels.

    If you want more information, check out sections 4.4.3 (Defocused PSFs performance) and 4.6 (Noise Budget) [esa.int].

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  • (Score: 2) by FatPhil on Wednesday February 12 2020, @09:40AM

    by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Wednesday February 12 2020, @09:40AM (#957145) Homepage
    I did not say that they would or should need or want to undo the blur. You're arguing against a straw man. Reread for comprehension this time.
    --
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