James Webb Space Telescope

I find it amazing that way out in space, with no atmosphere: The hot side of the heat shield is 130 degrees F.

Is that accurate?
 
Hmm...
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sculptor said:
I find it amazing that way out in space, with no atmosphere: The hot side of the heat shield is 130 degrees F.

Is that accurate?
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Yes. Photons from the Sun that aren't reflected from the telescope can only be absorbed, and their energy has to go somewhere; it heats the telescope.

The lack of an atmosphere means that the only way the telescope can lose heat is to radiate it away (as lower-energy photons). That process is far slower than the conduction/convection processes that happen in air.

The 5-layer heat shield is supposed to capture the light from the sun and radiate it away, including by reflecting light emitted from each layer back and forth and channelling it down the layers and out into space, away from the telescope's mirrors and instruments.

Once the telescope reaches equilibrium it will be radiating solar energy at the same rate that it receives it, which means the temperatures on the front and back of the shields will be approximately stable.
 
sculptor said:
I find it amazing that way out in space, with no atmosphere: The hot side of the heat shield is 130 degrees F. Is that accurate?
Click to expand...
Yep. No atmosphere to conduct away the heat. It would get conducted (and radiated away) on the other side - but the designers were very careful to add a LOT of insulation to prevent that.
 
"The entire Webb team is ecstatic at how well the first steps of taking images and aligning the telescope are proceeding. We were so happy to see that light makes its way into NIRCam," said Marcia Rieke, principal investigator for the NIRCam instrument and regents professor of astronomy at University of Arizona, in a statement."
 
geordief said:
"
James Webb: 'Fully focused' telescope beats expectations"
:)
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Ah. Answered before I had a chance to ask:
The "spike" structures were a function of the design of Webb's primary mirror, explained Mark McCaughrean from the European Space Agency (Esa).

"The shape of those 18 hexagons imprints a faint diffraction pattern that makes bright stars look like spiky snowflakes - this isn't a problem for the science, but will give Webb images a very distinctive look," he told BBC News.

"Indeed, the fact that we can see those spikes so crisply also confirms that the mirrors have been perfectly lined up - this is brilliant news."
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According to the text this would be the 3rd interloper from another star system dicovered and the first by the James Webb Telescope

Well done all those people involved

Screenshot_2022-03-26-03-35-35-88_40deb401b9ffe8e1df2f1cc5ba480b12.jpg

I spy with my big eye something beginning with interloper

I spy with my little eye - Dueling Banjos with a violin getting into the action :)


:)
 
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geordief said:
Don't think Webb has started work yet,has it?

Can't have discovered anything,surely?
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Still in the process of focusing the mirror, without going back to check think about another 6 weeks to go

But yes it has checked the focus already on a star and apparently found this inter star system interloper

:)
 
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