49 research outputs found

    The Science Performance of JWST as Characterized in Commissioning

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    This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures; https://iopscience.iop.org/article/10.1088/1538-3873/acb29

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

    Albrecht von Graefe and the beginning of modern ophthalmology Graefe year 2020

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    Albrecht von Graefe in the present, the past, and the future

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    Albrecht von Graefe (1828-1870) is the founder of this archive (1854) and the founder of modern ophthalmology. In 2020, the anniversary of his death will be observed for the 150th time. The 'German Ophthalmological Society' (DOG), also a Graefe foundation (1857), has therefore proclaimed a 'Graefe year.' In Berlin, his hometown, several Graefe-monuments exist. Ophthalmology owes Albrecht von Graefe numerous first discoveries such as excavation of the optic disc in glaucoma (1855), iridectomy in glaucoma (1857), or central artery occlusion (1859). But his after-effects are not only based on his clinical and scientific merits but also on his extraordinary, fascinating personality, which can be characterized by his spirit of internationality, friendship, self-criticism, love of truth, and modesty. Graefe became a myth not only because of his early death but also because he had apart from great successes, to accept human misfortunes at the same time. Albrecht von Graefe can be regarded as the conscience of ophthalmology in Germany

    Future through history

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