JoeSchmuckatelli Posted January 9, 2022 Share Posted January 9, 2022 (edited) 7 minutes ago, cubinator said: sdfsaefresfsef 7 minutes ago, cubinator said: There should be no way to mess that up with adjustable segments. There could be 18 ways to mess that up. Edited January 9, 2022 by JoeSchmuckatelli Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted January 9, 2022 Share Posted January 9, 2022 The first science images are expected in about six months. "We start with the mirrors off by millimeters, and we're driving them to be aligned within less than the size of a coronavirus, like to tens of nanometers," said Jane Rigby, Webb operations project scientist. "It's this very deliberate process that is time consuming." Rather than showing off initially blurry "first light" images in the next few weeks, "we want to make sure that the first images that the world sees ... do justice to this $10 billion telescope," she said. "So we are planning a series of 'wow' images to be released at the end of commissioning." Webb telescope deployments complete as side mirrors rotate into place - CBS News Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted January 9, 2022 Share Posted January 9, 2022 1 hour ago, JoeSchmuckatelli said: a series of 'wow' images is exactly what I'm hoping for. We need a new Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 9, 2022 Share Posted January 9, 2022 (edited) 3 hours ago, JoeSchmuckatelli said: Webb telescope deployments complete as side mirrors rotate into place - CBS News At the very left. "Momentum Flap" Flaps! They use flaps in vacuum! To manage the momentum! (Even if this looks more like a fin, but anyway.) And the whole thing looks like a sailboat. Aether exists! Spoiler 2 hours ago, JoeSchmuckatelli said: And here again! Edited January 9, 2022 by kerbiloid Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted January 9, 2022 Share Posted January 9, 2022 23 minutes ago, kerbiloid said: Aether exists My dear friends from the 1800s agree! Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted January 9, 2022 Share Posted January 9, 2022 Question - with the requirement of keeping the sun shield between the observatory and the sun, are there parts of the sky in the axis of the orbit that cannot be imaged? Quote Link to comment Share on other sites More sharing options...
Elthy Posted January 9, 2022 Share Posted January 9, 2022 No. The telescope can only image a "ring" of the sky at a given moment, but as it circles around the sun that ring will hit every part of the sky within a year. Scott Manley has more details in his video about the JWST. Quote Link to comment Share on other sites More sharing options...
cubinator Posted January 9, 2022 Share Posted January 9, 2022 2 hours ago, JoeSchmuckatelli said: Question - with the requirement of keeping the sun shield between the observatory and the sun, are there parts of the sky in the axis of the orbit that cannot be imaged? It has about 60% of the sky available at any time. As it goes around the sun, it can see the full sky over time. Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted January 9, 2022 Share Posted January 9, 2022 1 hour ago, cubinator said: It has about 60% of the sky available at any time. As it goes around the sun, it can see the full sky over time. Yeah - I'm getting that - but wondered if there was a region above or below the 'pole' of the orbit that it could not resolve b/c of the shade Quote Link to comment Share on other sites More sharing options...
HebaruSan Posted January 9, 2022 Share Posted January 9, 2022 33 minutes ago, JoeSchmuckatelli said: Yeah - I'm getting that - but wondered if there was a region above or below the 'pole' of the orbit that it could not resolve b/c of the shade Here is a direct link to Scott Manley's detailed explanation of all the orbits and angles (timestamp 6:23): Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted January 9, 2022 Share Posted January 9, 2022 8 minutes ago, HebaruSan said: Scott Manley's detailed explanation of all the orbits and angles (timestamp 6:23 Thanks - that was great! Interestingly, he says that what actually happens is the exact opposite of what I feared: there are two small areas at the poles that are constantly viewable. Wow. Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted January 10, 2022 Share Posted January 10, 2022 After all individual mirror segment deployments are completed, the detailed optical mirror alignment process begins which is about a 3 month process. In parallel, as temperatures cool enough, instrument teams will turn on their instruments and begin each instrument's commissioning process. Mirrors Webb/NASA Quote Link to comment Share on other sites More sharing options...
tomf Posted January 10, 2022 Share Posted January 10, 2022 It will be like going to the opticians "can you read the middle line of letters for me please. And is this better or worse, better or worse?" for 6 months solid. Quote Link to comment Share on other sites More sharing options...
Nuke Posted January 12, 2022 Share Posted January 12, 2022 its like truing a bicycle rim.. every spoke you adjust affects the tension on all the other spokes. takes forever. eventually you get to a point where its good enough to use. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 12, 2022 Share Posted January 12, 2022 Spoiler No problem. mousewheel rim + several intracycles + epicycling gearing Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted January 14, 2022 Share Posted January 14, 2022 For those wanting more info, the current blog is a pretty good read: James Webb Space Telescope (nasa.gov) Quote Each mirror now needs to be deployed out by 12.5 millimeters (about half an inch) to get the pegs clear from the sockets. This will give the mirrors ‘room to roam’ and let them be readied in their starting positions for alignment. ... At full speed, it takes about a day to move all the segments by just 1 millimeter. It’s about the same speed at which grass grows! Quote Link to comment Share on other sites More sharing options...
VaPaL Posted January 14, 2022 Share Posted January 14, 2022 1 hour ago, JoeSchmuckatelli said: 12.5 millimeters I did not expected to be this much, I thought they would be much closer to final position... Maybe some small alignment due to rocket vibration or assembly tolerance, but only that Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted January 14, 2022 Share Posted January 14, 2022 3 minutes ago, VaPaL said: I did not expected to be this much, I thought they would be much closer to final position... Maybe some small alignment due to rocket vibration or assembly tolerance, but only that Apparently they wanted to make durned sure the mirrors were safe from vibrations (Abrupt clamp release, anyone?). Like you, I'm surprised - but this certainly explains why they're spending so much time releasing and testing each mirror. ... Watching the grass grow? Daaaaang. Quote Link to comment Share on other sites More sharing options...
VaPaL Posted January 14, 2022 Share Posted January 14, 2022 10 minutes ago, JoeSchmuckatelli said: Watching the grass grow? Daaaaang. Mirror position x time: Quote Link to comment Share on other sites More sharing options...
Elthy Posted January 15, 2022 Share Posted January 15, 2022 Does anyone have technical details on those acctuators? How do they work, how are they so precise? Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted January 15, 2022 Share Posted January 15, 2022 8 hours ago, Elthy said: Does anyone have technical details on those acctuators? How do they work, how are they so precise? I have no idea, but I would assume something similar to a worm-gear screw jack: slow but relatively torquey, allowing for great precision. Quote Link to comment Share on other sites More sharing options...
wumpus Posted January 15, 2022 Share Posted January 15, 2022 23 hours ago, VaPaL said: Mirror position x time: I once described the movie 2001 as "watching a glacier move", granted that was watching a VHS tape on a 1980s CRT TV. Watching the whole thing later on a real movie theater with Dolby sound was enjoyable. Perhaps NASA didn't include cameras partly to spare people the nagging feeling that they should be watching the JWST unfold. Quote Link to comment Share on other sites More sharing options...
magnemoe Posted January 17, 2022 Share Posted January 17, 2022 On 1/15/2022 at 5:31 PM, StrandedonEarth said: I have no idea, but I would assume something similar to a worm-gear screw jack: slow but relatively torquey, allowing for great precision. Probably now add an servo motor to it, might even have an gear box for more accuracy but making it even slower. Part of the reason why its slow is because its purpose is to bend the glass an fraction of an wavelength and you do not want this to break the mirror if one of them stops for an reason. Quote Link to comment Share on other sites More sharing options...
cubinator Posted January 17, 2022 Share Posted January 17, 2022 (edited) 39 minutes ago, magnemoe said: Probably now add an servo motor to it, might even have an gear box for more accuracy but making it even slower. Part of the reason why its slow is because its purpose is to bend the glass an fraction of an wavelength and you do not want this to break the mirror if one of them stops for an reason. The mirror is made of beryllium metal coated in gold, not glass. It won't break. Edited January 17, 2022 by cubinator Quote Link to comment Share on other sites More sharing options...
VaPaL Posted January 18, 2022 Share Posted January 18, 2022 (edited) EDIT: Not aligned... deployed* Edited January 18, 2022 by VaPaL Quote Link to comment Share on other sites More sharing options...
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