James Webb Telescope

Puppycow said:
A slightly more serious possibility is that six months is a conservative estimate, which leaves room for the working out of unanticipated issues that might come up. If such issues do not materialize and everything goes smoothly, maybe it will be ready before six months.

E.g., like how it turned out that they actually have enough fuel for significantly more than 10 years of service. They lowballed the estimate on the theory that if there are going to be any surprises, it would be nice if they are on the up-side rather than the down-side.
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Which you somehow translate into ******** on NASA for doing the right thing.
 
Puppycow said:
E.g., like how it turned out that they actually have enough fuel for significantly more than 10 years of service. They lowballed the estimate on the theory that if there are going to be any surprises, it would be nice if they are on the up-side rather than the down-side.
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It's a basic principle of customer service. Promise low and deliver high.
 
theprestige said:
Which you somehow translate into ******** on NASA for doing the right thing.
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I don't know why you're being so irritable. Puppycow made a half-serious observation that given the opportunity, engineers would play. I don't think that's at all an unreasonable thing to say, much less constitutes ******** on NASA.
 
arthwollipot said:
I don't know why you're being so irritable. Puppycow made a half-serious observation that given the opportunity, engineers would play. I don't think that's at all an unreasonable thing to say, much less constitutes ******** on NASA.
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Puppycow thought it would be funny to joke about how NASA is mercenary and anti science. Yay.
 
If you bought a new pair of calipers, you wouldn't just take it out on the shop floor and start using it, not in a well-run organization anyway. Calibration involves several steps, starting with repeatability and progressing through statistical accuracy and precision assessment. A piece of kit this complex will take some time to sort out.
 
a_unique_person said:
So they'll be taking pictures they can't verify the accuracy of. I vote we don't wait
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As I understand it, the first pictures will be toward some particular light source, and the resulting image is supposed to have version for each mirror segment. 18?

The idea will be to gradually get all the segments to resolve the light source as a single image. That, on top of having to cool all the way down, will take some time.
 
sackett said:
My gf asks, Why 6 months? I explained patiently that the astronomers have to go out to the parking lot and duke to see who gets viewing time.

She thought I was joking, of course. Women!
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The real reason is to trick the Rebels into attacking our fully armed and operational battle station scientific instrument.
 
Trebuchet said:
More of an anachronism, I think. I still have a lovely bamboo one. It's self lubricating and runs so smooth. I'd go to exams with two of them, the bamboo for most things and a plastic one for scales it didn't have.
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That... still works as a euphemism. :p
 


Another worthy video from Launch Pad Astronomy, explains how and why the telescope orbits an empty point in space.
 
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If anyone's interested, there are a few new doodads on the Where's Webb page:

https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric

You can now see the temperatures in Kelvin, as well as Celsius or Fahrenheit. In addition, you can now see the individual temperatures of five instruments:
1) MIRI Bench: Mid InfraRed Instrument
2) NIRCam Bench: Near InfraRed Camera
3) NIRSpec Bench: Near InfraRed Spectrometer
4) FGS/NIRISS Bench: Fine Guidance Sensor / Near InfraRed Imager and Slitless Spectrograph
5) FSM Fine Steering Mirror

The temperatures are updated once a day.
 
Puppycow said:
If anyone's interested, there are a few new doodads on the Where's Webb page:

https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric

You can now see the temperatures in Kelvin, as well as Celsius or Fahrenheit. In addition, you can now see the individual temperatures of five instruments:
1) MIRI Bench: Mid InfraRed Instrument
2) NIRCam Bench: Near InfraRed Camera
3) NIRSpec Bench: Near InfraRed Spectrometer
4) FGS/NIRISS Bench: Fine Guidance Sensor / Near InfraRed Imager and Slitless Spectrograph
5) FSM Fine Steering Mirror

The temperatures are updated once a day.
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That's quite the difference between the hot and the cold side of the telescope.
Much more than what I had expected.
 
The temperatures are really getting down there now

Primary Mirror -218°C (55K)
Instrument Radiator -215°C (58K)
Fine Steering Motor -220°C (53K)

Instruments
MIRI -129°C (144K)
NIRcam -186°C (88K)
NIRSpec -175°C (98k)
FGS/NIRISS 175°C (100K)
 
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