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Post by High Sierra Fan on Jan 1, 2022 15:41:21 GMT -8
The most amazing part, to me, is that last set of panels---part of the mirror---that fold out and then join the main mirror sections. Remember that for the image from the telescope to be perfectly clear, the mirror surface needs to be accurately figured to within 1/4 wavelength of light. And thus those last panels need to deploy into position with that kind of accuracy in all three dimensions. The mind boggles. Then again, my mind boggles a lot these days. The panels themselves are flexible and get tuned individually for the last bit of alignment. “ Achieving A Single Perfect Focus- Actuators Once in space, getting these mirrors to focus correctly on faraway galaxies is another challenge. Actuators, or tiny mechanical motors, provide the answer to achieving a single perfect focus. The primary mirror segments and secondary mirror are moved by six actuators that are attached to the back of each mirror piece. The primary mirror segments also have an additional actuator at its center that adjusts its curvature. The telescope's tertiary mirror remains stationary. Lee Feinberg, Webb Optical Telescope Element Manager at NASA Goddard explains, "Aligning the primary mirror segments as though they are a single large mirror means each mirror is aligned to 1/10,000th the thickness of a human hair. What's even more amazing is that the engineers and scientists working on the Webb telescope literally had to invent how to do this."” jwst.nasa.gov/content/observatory/ote/mirrors/index.htmlI suspect they learned a lesson from the Hubble being ground wrong and needing a corrective lens refit via a space shuttle repair visit; something not possible out at L2. ETA: a similar technique has been used in ground based telescopes: adaptive optics. www.eso.org/public/teles-instr/technology/adaptive_optics/
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davesenesac
Trail Wise!
Our precious life is short within eternity, don't waste it!
Posts: 1,710
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Post by davesenesac on Jan 5, 2022 8:52:44 GMT -8
Finally, most of the big mechanical unfolding is now complete. Well done!
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Post by High Sierra Fan on Jan 7, 2022 20:29:40 GMT -8
Last I’d read one mirror wing segment to go. Getting past the sun shield tensioning, just about half the single point of failure and they lose the mission points, was a huge relief.
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rebeccad
Trail Wise!
Writing like a maniac
Posts: 12,667
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Post by rebeccad on Jan 8, 2022 8:32:42 GMT -8
Just heard (a little slow) on NPR that they’ve completed deployment, all successful!
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swiftdream
Trail Wise!
the Great Southwest Unbound
Posts: 543
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Post by swiftdream on Jan 8, 2022 10:40:13 GMT -8
Heard it has fully deployed this morning. I’ve followed Hubble closely and look forward to images from Web after they align and calibrate it, about five months from now.
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driftwoody
Trail Wise!
Take the path closer to the edge, especially if less traveled
Posts: 14,974
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Post by driftwoody on Jan 9, 2022 11:05:51 GMT -8
Heard it has fully deployed this morning. I’ve followed Hubble closely and look forward to images from Web after they align and calibrate it, about five months from now. So much invested with so many potential points of failure, this is a much needed good news story in these troubled times.
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Post by High Sierra Fan on Jan 9, 2022 15:24:36 GMT -8
ESA has a mission specifically looking at exo planets which sounds interesting. JWST is doing some of that but in a narrower spectrum. I didn’t catch the design in a quick glance. sci.esa.int/web/arielIt’s also heading for L2, going to get crowded over there?
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Post by nickhowes on Jan 10, 2022 5:50:33 GMT -8
I think this is one of the better articles on JWST. The first part of the article is all about the difficulties and risks of launch and deployment, much of which is now complete. After that, it gets down to the potential science, which is quite exciting IMHO.
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Post by ecocentric on Jan 10, 2022 11:26:44 GMT -8
the mirror surface needs to be accurately figured to within 1/4 wavelength of light. ...easier for infrared than ultraviolet and much easier than detecting gamma. The technology is amazing. Many question that value of this kind of fundamental research, but one of the dividends of radio astronomy is Magnetic Resonance Imaging, which has revolutionized medical imagining.
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Post by High Sierra Fan on Jan 25, 2022 22:25:10 GMT -8
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Post by Coolkat on Feb 28, 2022 8:53:46 GMT -8
Getting closer...
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Post by swimswithtrout on Mar 15, 2022 0:04:53 GMT -8
And the moment we've all been waiting for
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Post by swimswithtrout on Mar 15, 2022 2:15:48 GMT -8
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Post by swimswithtrout on Mar 15, 2022 2:16:34 GMT -8
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Post by swimswithtrout on Mar 15, 2022 2:17:09 GMT -8
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