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James Webb Telescope

Latest cold side temperatures.

Primary Mirror: -164°C (down from -147°C yesterday)
Instrument Radiator: -199°C (down from -197°C yesterday)
 
Actually, some clocks probably have parts that move as slow as grass grows. E.g. a wrist watch (analog type) that tells the day of the month, for example. How much does a blade of grass grow in a day? Google says 0.06 to 0.2 inches/day. About the same distance that that part on a wristwatch moves in a day.
 
Puppycow said:
Actually, some clocks probably have parts that move as slow as grass grows. E.g. a wrist watch (analog type) that tells the day of the month, for example. How much does a blade of grass grow in a day? Google says 0.06 to 0.2 inches/day. About the same distance that that part on a wristwatch moves in a day.
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Most often, the date indicator driving wheel of a wristwatch rotates at half the speed of the 12-hour wheel, rotating once per 24 hours. The reason the date ring rotates only 1/31 of a full rotation every 24 hours is that the driving wheel has a tooth that briefly engages one of the 31 teeth on the date ring, just long enough to shove that ring 1/31 of a full rotation.
 
Puppycow said:
Actually, some clocks probably have parts that move as slow as grass grows. E.g. a wrist watch (analog type) that tells the day of the month, for example. How much does a blade of grass grow in a day? Google says 0.06 to 0.2 inches/day. About the same distance that that part on a wristwatch moves in a day.
Click to expand...


I recall reading about a Renaissance era clock that has an axial precession mechanism, completing one revolution every 26,000 years. The Clock of the Long Now probably has a dial for that too.
 
The port primary mirror wing has begun to deploy



ETA: Update 14:31 ET - The Port Primary Mirror Wing is fully deployed and latched.
 
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smartcooky said:
The port primary mirror wing has begun to deploy



ETA: Update 14:31 ET - The Port Primary Mirror Wing is fully deployed and latched.
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I know there's really nothing to see except Mission Control, but I've had a hard time figuring out when and what they're showing on NASA TV, by their schedule. It's changed a couple times in the last day or so -- even said the deployment was tomorrow! Maybe that's the completion time? Ah well, I'll keep checking.
 
I went looking for a video showing how the telescope deployed and found one but honestly the part that's going to stick with me is the narrator repeatedly pronouncing Ariane as "aryan".
 
alfaniner said:
I know there's really nothing to see except Mission Control, but I've had a hard time figuring out when and what they're showing on NASA TV, by their schedule. It's changed a couple times in the last day or so -- even said the deployment was tomorrow! Maybe that's the completion time? Ah well, I'll keep checking.
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Last I heard was there is a briefing tomorrow; NASA TV should start showing about 9AM EST.
 
alfaniner said:
I know there's really nothing to see except Mission Control, but I've had a hard time figuring out when and what they're showing on NASA TV, by their schedule. It's changed a couple times in the last day or so -- even said the deployment was tomorrow! Maybe that's the completion time? Ah well, I'll keep checking.
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Maybe this helps:

https://www.nasa.gov/nasalive

Looks like the next event is:
(All times Eastern U.S. time, which equates to UTC-5.)

January 8, Saturday
No earlier than 9 a.m. - Live coverage of the unfolding of the second of the James Webb Space Telescope's primary mirror wings, marking the end of the observatory deployments.
No earlier than 1:30 p.m. - NASA will hold a media briefing as soon as possible after the end of the live broadcast coverage of Webb’s final deployments.
10:40 p.m. - Coverage of the launch of a sounding rocket carrying an X-ray astronomy instrument from NASA's Wallops Flight Facility in Virginia.
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Puppycow said:
Are the fine mirror adjustments done manually or by an algorithm?
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There's almost certainly an algorithm, although I bet the telescope also reports all the data used for the algorithm so that NASA can double check the results.
 
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