James Webb Telescope

I wondered whether they can take any more test images while they are waiting for MIRI to cool? Just to give it a test drive and maybe get a few nice images to show to the public?
 
Probably interest the folk following this telescope, big brother is still managing some firsts:

https://www.livescience.com/hubble-most-distant-star-ever-seen

....Hubble Space Telescope recently detected a star that is the most distant ever seen. Located 28 billion light-years from Earth, the ancient object — which could be a single star or a double-star system — may be up to 500 times more massive than our sun; it's also millions of times brighter than the sun and was born when the universe was young....​
 
Darat said:
Probably interest the folk following this telescope, big brother is still managing some firsts:

https://www.livescience.com/hubble-most-distant-star-ever-seen

....Hubble Space Telescope recently detected a star that is the most distant ever seen. Located 28 billion light-years from Earth, the ancient object — which could be a single star or a double-star system — may be up to 500 times more massive than our sun; it's also millions of times brighter than the sun and was born when the universe was young....​
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Amazing to think that it's still going after all this time!

[/sarcasm]
 
Darat said:
Probably interest the folk following this telescope, big brother is still managing some firsts:

https://www.livescience.com/hubble-most-distant-star-ever-seen

....Hubble Space Telescope recently detected a star that is the most distant ever seen. Located 28 billion light-years from Earth, the ancient object — which could be a single star or a double-star system — may be up to 500 times more massive than our sun; it's also millions of times brighter than the sun and was born when the universe was young....​
Click to expand...

As I posted over at Cosmoquest, that's a record that JWST will be breaking repeatedly over the next few months.
Except it's all a hoax anyhow, because it's a NASA ruse, or something.
Do not expect to make much sense out of the OP's nonsense in that link.
 
Trebuchet said:
As I posted over at Cosmoquest, that's a record that JWST will be breaking repeatedly over the next few months.
Except it's all a hoax anyhow, because it's a NASA ruse, or something.
Do not expect to make much sense out of the OP's nonsense in that link.
Click to expand...
What did I miss? The OP in that thread appears correct.
 
RecoveringYuppy said:
What did I miss? The OP in that thread appears correct.
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You would have had to back up to another post to see why the thread was created. Basically the OP appeared to be claiming that the diffraction spikes were added by nasa intentionally as part of the photoshop process. That particular post wasn't put in the thread, but was the start of it...

It's a feeble ruse by an antiquated agency grasping at straws for its fleeting abilities. Coincidentally, the oft delayed, over budget JWST just happens to take a "photo" of the traditional rendering of, The Star of Bethlehem. I'll be on, Craigslist buying a bridge.
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BowlOfRed said:
You would have had to back up to another post to see why the thread was created. Basically the OP appeared to be claiming that the diffraction spikes were added by nasa intentionally as part of the photoshop process. That particular post wasn't put in the thread, but was the start of it...
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These CTs act like they were born yesterday and that CT websites are literally the first thing they read on any particular subject matter. The guy seems to think false-color presentations of images taken in non-visible light are sus. I guess he things volume-rendering CT scans are a scam, too. Actually, he very possibly does.
 
Trebuchet said:
As I posted over at Cosmoquest, that's a record that JWST will be breaking repeatedly over the next few months.
Except it's all a hoax anyhow, because it's a NASA ruse, or something.
Do not expect to make much sense out of the OP's nonsense in that link.
Click to expand...

Looks like a motte and bailey troll.

http://blog.practicalethics.ox.ac.uk/2014/09/motte-and-bailey-doctrines/

For my original purposes the desirable but only lightly defensible territory of the Motte and Bailey castle, that is to say, the Bailey, represents philosophical propositions with similar properties: desirable to their proponents but only lightly defensible. The Motte represents the defensible but undesired propositions to which one retreats when hard pressed.
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The poster suggested something frankly ridiculous, but in a roundabout way. Then when challenged, retreated to a more defensible position, but one that is silly (trivial). We are already aware that the JWST takes images of wavelengths that are not visible to the human eye. So what we see is obviously not exactly what the telescope sees. It has to be translated into light wavelengths that our eyes can see.

The more ridiculous suggestion was that the six diffraction spikes were selected to make it appear like a Star of David.
 
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Except, the traditional rendering of the Star of Bethlehem is cross-shaped.
 
Puppycow said:
The more ridiculous suggestion was that the six diffraction spikes were selected to make it appear like a Star of David.
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That is a feature of just about every SLR camera on the planet the moment you stop down to take a photo..... its a world-wide Jewish conspiracy I tells ya!!
 
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Green = Instrument target temperature reached

Frame and mirror
Primary Mirror -230° 43K
Instrument Radiator -236° (37K)
Fine Steering Motor -240° (33K)

Instruments
MIRI -220° (53K)
NIRcam-235° (39K)
NIRSpec-238° (35K)
FGS/NIRISS -233° (40K)

MIRI's temperature is still falling rapidly with the cryo-cooler running. At this rate if should reach its target temaperature of 7K in about two weeks

FGS/NIRISS has now reached its target temperature of 40K
 
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smartcooky said:
Green = Instrument target temperature reached

Frame and mirror
Primary Mirror -230° 43K
Instrument Radiator -236° (37K)
Fine Steering Motor -240° (33K)
Click to expand...

Are these ones not green because they haven't reached their target temperatures or do they not have target temperatures? The primary mirror is the only one that looks like it might be a smidge high.
 
Puppycow said:
Are these ones not green because they haven't reached their target temperatures or do they not have target temperatures? The primary mirror is the only one that looks like it might be a smidge high.
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As far as I know the Fine Steering Motor and the Instrument Radiator do not have specific target temperatures, they are passively cooled by being on the shadow side of the sun-shield, while three of the instruments are semi-actively cooled by the Instrument Radiator, the fourth, MIRI is actively cooled by the cryo-cooler.

The Primary Mirror is expected to be below 50K, but keep in mind that this is just an average, because its not "a" mirror, it is 18 mirrors. The final temperatures will still have a spread of 15 to 20 kelvins across all 18. While 40K would be great, is not vital in the way that the instrument temperatures are.

I read something interesting a while ago about how the cooling works for NIRCam, NIRSpec and NIRISS using the sun-shield. Apparently the amount of energy (in milliwatts) that gets through the sun-shield, plus the heat generated by electronics of the three instruments, is exactly balanced against the loss of heat into space, in order to achieve a "steady state temperature". They calculated what the heat loss to space would be, and the heat that would be would be generated by the electronics, and then designed the sun-shield to allow just the right amount of heat through to keep the instrument temperatures stable.

The more I read about the JWST, the I am gobsmacked by the extraordinary level of engineering involved.
 
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