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My (current) answer is that this question remains unanswered! Whilst it is clear that segmented mirrors (of any shape) create problems with the "point spread function"; it is also clear that -- at least in the case of symmetrically arranged, circular approximation using hexagonal elements -- this is a 'solved problem' to some greater or lesser ...


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As @uhoh pointed out, when you change the shape of a mirror from something other than a circular disc, "things" can happen to the PSF (point spread function) which may lead to reduced quality of particular spatial frequencies. The simplest example is a primary with a circular hole in the center, a common design for reflecting telescopes where the ...


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How does IXPE measure polarization? Short answer: Electrons in the detector are preferential emitted in the direction of the polarization of the incident photon and then detected. Quoting from NASA's IXPE: Polarization Detection page: IXPE will have three identical X-ray telescopes, with polarization detectors at each focus. The detectors, called Gas Pixel ...


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All modes can be used. But for bright targets, observations are limited to specific filters, subarrays, regions of the target planet, or spectral intervals. James Norwood and colleagues wrote a paper on this topic, although the full answer is complicated because of the "subset of the instrument modes" part. The simplest answer to understand is for ...


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There are approved proposals for Cycle 1 to point the JWST at The Jovian system Jupiter's great red spot Mars Saturn and its moons and rings In those PDFs, they describe exactly what instruments they want to point where, but to summarize as far as I can tell they're planning to try to use pretty much all of the available instruments to image Jupiter and ...


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Each of James Webb's mirror segments are adjustable through seven small motors, called actuators. Due to thermal variations, the segments do indeed need to be re-adjusted occasionally. Exactly how often is a compromise between desired image quality and valuable science observation time, as argued by Park et al. (2017) who develop a thermal model, but don't ...


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Welcome "akostadinov", and welcome to me, too! Indeed, a great question.. In an attempt to start an answering discussion, understand each of the Webb's 18 primary mirrors have I believe 5 motorized adjustment points (correction - 6 actuator motors!), for just what you're asking! Yes, once everything is locked down and deployed, there will be an ...


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In the video, the white dots represent 14000 asteroids, and the green tracks are 200 of the brightest asteroids. These are from standard catalogues. Gaia has detected about 1700 asteroids, but most of these were already known. The video shows four newly discovered object, in pink. They have provisional designations 2018 YK4, 2018 XL4, 2018 YM4 and 2019 CZ10....


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