James Webb Telescope - Page 3

Pixel42 · 3rd June 2021, 08:58 PM

I think of pure scientific research as akin to music or art - we do these things to enrich our minds, not our material welfare. It's what makes us civilised, makes us different to the animals from which we evolved. Any practical benefits which eventually emerge are just an added bonus.

slyjoe · 3rd June 2021, 10:18 PM

Originally Posted by Pixel42

I think of pure scientific research as akin to music or art - we do these things to enrich our minds, not our material welfare. It's what makes us civilised, makes us different to the animals from which we evolved. Any practical benefits which eventually emerge are just an added bonus.

And, don't forget the other difference, we use cutlery.

Ziggurat · 4th June 2021, 03:50 AM

Originally Posted by Pixel42

I think of pure scientific research as akin to music or art - we do these things to enrich our minds, not our material welfare. It's what makes us civilised, makes us different to the animals from which we evolved. Any practical benefits which eventually emerge are just an added bonus.

I think it was Feynman who said physics is like sex: it has practical results, but that’s not why we do it.

erwinl · 4th June 2021, 04:25 AM

Originally Posted by Ziggurat

Sure, but they don't have the budget for two of these. And with the budget they do have, any telescope they could build two of wouldn't be as good. And they'd rather have less time on a better telescope than more time on inferior ones.

ETA: I can see a use case for multiple identical space telescopes, though. With radio astronomy, building multiple telescopes to form a giant array allows you to get vastly better diffraction limits on your signal than you can with a single telescope.

Is that possible for Visible Light telescopes as well? Or it it not practical enough for that frequency band of the spectrum?

Belz... · 4th June 2021, 04:38 AM

Originally Posted by Samson

I cant imagine any reason that moving this telescope would be unplanned for.

...what?

Belz... · 4th June 2021, 04:39 AM

Originally Posted by jonesdave116

Yep. Given that it will be at at the L2 point, fixing it is not going to be easy. Or cheap.

More like too hard to even attempt.

A lot of money down the drain if this fails. Maybe they should make wider rocket heads, instead.

Belz... · 4th June 2021, 04:40 AM

Originally Posted by Samson

Again, 10 billion is now small change for Gate Musk Bezos Zukerberg Buffet Apple etc.

Er... no it isn't.

Quote:

A good that includes avoiding another Chuxilliub

What do asteroids have to do with the telescope???

Samson · 4th June 2021, 05:00 AM

Originally Posted by Belz...

Er... no it isn't.

What do asteroids have to do with the telescope???

I bet T rex would wish even a suboptimal device like James Webb had warned him.

(Honey i shrunk the kids)

Belz... · 4th June 2021, 05:27 AM

Originally Posted by Samson

I bet T rex would wish even a suboptimal device like James Webb had warned him.

(Honey i shrunk the kids)

Are you high right now? I can't make heads or tails of your posts.

Ziggurat · 4th June 2021, 05:32 AM

Originally Posted by erwinl

Is that possible for Visible Light telescopes as well? Or it it not practical enough for that frequency band of the spectrum?

I don’t think we can do it for optical band. You need to be able to accurately time the phase of the signal between your different detectors, and I don’t think we really have that capability for visible light in the same way.

Ziggurat · 4th June 2021, 06:50 AM

Originally Posted by erwinl

Is that possible for Visible Light telescopes as well? Or it it not practical enough for that frequency band of the spectrum?

The other thing is that using multiple telescopes as a giant interferometer only helps overcome the diffraction limit on angular resolution, it doesn't really amplify the signal strength. So if you've got a bright source that provides plenty of signal and you just need better angular resolution, using this can help a lot. If you're limited on signal intensity, this won't help much.

But it turns out I was wrong, there are actually some optical interferometer telescopes, for example:
https://en.wikipedia.org/wiki/Navy_P...Interferometer
But in general, it's not used as much for optical as radio. For one, I think it's easier with radio. Two, radio benefits more, since the diffraction limit is much worse for a single radio telescope dish than for an optical telescope. And three, optical telescopes are often signal limited anyways, so you need big dishes anyways, and that helps with the diffraction limit as a side effect.

erwinl · 4th June 2021, 07:15 AM

Originally Posted by Ziggurat

The other thing is that using multiple telescopes as a giant interferometer only helps overcome the diffraction limit on angular resolution, it doesn't really amplify the signal strength. So if you've got a bright source that provides plenty of signal and you just need better angular resolution, using this can help a lot. If you're limited on signal intensity, this won't help much.

But it turns out I was wrong, there are actually some optical interferometer telescopes, for example:
https://en.wikipedia.org/wiki/Navy_P...Interferometer
But in general, it's not used as much for optical as radio. For one, I think it's easier with radio. Two, radio benefits more, since the diffraction limit is much worse for a single radio telescope dish than for an optical telescope. And three, optical telescopes are often signal limited anyways, so you need big dishes anyways, and that helps with the diffraction limit as a side effect.

Thanks!

A bit as I suspected.
But I had no idea concerning present capabilities and/or benefits so I thought, I’d ask.

RecoveringYuppy · 4th June 2021, 08:22 AM

Originally Posted by erwinl

Is that possible for Visible Light telescopes as well? Or it it not practical enough for that frequency band of the spectrum?

It's starting to be practical.

ETA: helps if I actually add the link, and I see Ziggurat already posted on this issue. https://www.nature.com/articles/464820a

Blue Mountain · 4th June 2021, 12:46 PM

Originally Posted by Belz...

Er... no it isn't.

What do asteroids have to do with the telescope???

Originally Posted by Samson

I bet T rex would wish even a suboptimal device like James Webb had warned him.

(Honey i shrunk the kids)

I'm not sure how the "Honey, I Shrunk the Kids" remark figures into Samson's post, but he's alluding to programs such as NASA's Near-Earth Object Observations Program, which scans the sky looking for things on a collision course with Earth. Of greatest concern something like the object that caused the Chicxulub crater and also wiped out the dinosaurs, which is what Samson was referring to when he mentioned T. Rex.

As humans we're also interested in smaller objects like the one that caused the Tunguska event back in 1908: imagine the carnage it could have caused had it occurred over a populated area instead of remote Siberia.

See also the Chelyabinsk meteor, and other modern impact events.

I'm not sure the JWST will help with near Earth observation programs, but we do have Earth based telescopes that are continually searching for potential impact objects.

Belz... · 4th June 2021, 01:11 PM

Originally Posted by Blue Mountain

I'm not sure how the "Honey, I Shrunk the Kids" remark figures into Samson's post, but he's alluding to programs such as NASA's Near-Earth Object Observations Program, which scans the sky looking for things on a collision course with Earth. Of greatest concern something like the object that caused the Chicxulub crater and also wiped out the dinosaurs, which is what Samson was referring to when he mentioned T. Rex.

As humans we're also interested in smaller objects like the one that caused the Tunguska event back in 1908: imagine the carnage it could have caused had it occurred over a populated area instead of remote Siberia.

See also the Chelyabinsk meteor, and other modern impact events.

I'm not sure the JWST will help with near Earth observation programs, but we do have Earth based telescopes that are continually searching for potential impact objects.

It won't. It has nothing to do with it, which is why samson's post is puzzling. That's what I would say if samson's posts usually made sense.

Roboramma · 4th June 2021, 11:04 PM

Originally Posted by Belz...

It won't. It has nothing to do with it, which is why samson's post is puzzling. That's what I would say if samson's posts usually made sense.

Exactly. And I actually pointed this out to Samson earlier, so it's weird that he keeps bringing it up.

I suppose it's possible that if a potential problem asteroid or comet was noticed with some other instrument, JWST could be pointed in that direction and potentially give a more accurate measurement of its orbit. I'm not sure if JWST would be better than other telescopes for that job, or how much we could potentially gain from it in that use.

But, as you say, in general James Webb isn't involved in cataloging asteroids, so it doesn't seem to have much to do with the issues of potential impacts.

RecoveringYuppy · 5th June 2021, 08:03 AM

Originally Posted by Roboramma

Exactly. And I actually pointed this out to Samson earlier, so it's weird that he keeps bringing it up.

I suppose it's possible that if a potential problem asteroid or comet was noticed with some other instrument, JWST could be pointed in that direction and potentially give a more accurate measurement of its orbit. I'm not sure if JWST would be better than other telescopes for that job, or how much we could potentially gain from it in that use.

But, as you say, in general James Webb isn't involved in cataloging asteroids, so it doesn't seem to have much to do with the issues of potential impacts.

Radar is the best way to accurately track asteroids. But the world is a bit short on that now that Arecibo is gone.

Puppycow · 17th September 2021, 04:58 AM

Einstein ring captured by Hubble

Two galaxies with a distant quasar behind them.

Linky

And, the JWST now has an "official" launch date of December 18th:

https://www.bbc.com/news/science-environment-58498676

Quote:

The $10bn James Webb Space Telescope is expected to launch on 18 December.

Yes, countless targeted lift-offs have come and gone in the past, but this one has a reality to it that the others didn't: the successor observatory to Hubble is now actually built.

All that is required is to ship the finished telescope to French Guiana, put it on the top of an Ariane rocket, light the engines and stand well back.

a_unique_person · 17th September 2021, 11:14 PM

Fingers crossed.

Segnosaur · 18th September 2021, 06:27 AM

Anyone know why it is being launched from French Guiana and not from KSC? (I know that there is European involvement in the project, but since the telescope was assembled in California, transporting it overseas seems like an unnecessary risk/expense.)

Sent from my LM-X320 using Tapatalk

jadebox · 18th September 2021, 06:49 AM

Originally Posted by Segnosaur

Anyone know why it is being launched from French Guiana and not from KSC? (I know that there is European involvement in the project, but since the telescope was assembled in California, transporting it overseas seems like an unnecessary risk/expense.)

Sent from my LM-X320 using Tapatalk

The ESA offered to launch the telescope in exchange for time using the telescope.

Garrison · 18th September 2021, 10:31 AM

If it was delayed much longer it could have been launching on Starship.

Pope130 · 18th September 2021, 05:36 PM

Originally Posted by Segnosaur

Anyone know why it is being launched from French Guiana and not from KSC? (I know that there is European involvement in the project, but since the telescope was assembled in California, transporting it overseas seems like an unnecessary risk/expense.)

Sent from my LM-X320 using Tapatalk

One factor is that French Guiana is closer to the equator, getting more use from the Earth's rotational speed.

RecoveringYuppy · 18th September 2021, 06:32 PM

Originally Posted by Pope130

One factor is that French Guiana is closer to the equator, getting more use from the Earth's rotational speed.

That's not much of a gain even for things headed toward equatorial GEO. Won't that gain come at the cost of having to change the orbital plane later? Not sure what the exact demands are of the final orbit.

arthwollipot · 19th September 2021, 09:10 PM

There's also the issue that the contracts have been signed for ages. It could have gone up on a SpaceX Falcon Heavy, but instead it's going up on an older Ariane.

jadebox · 19th September 2021, 09:31 PM

Again, the reason the telescope is being launched on an Ariane is that NASA negotiated a deal in exchange for observation time using the telescope.

Quote:

Why is NASA's most expensive scientific instrument ever launching on a European rocket? Because the European Space Agency is conducting the launch for NASA in return for a share of observation time using the infrared telescope.

-- https://arstechnica.com/science/2021...e-launch-date/

arthwollipot · 19th September 2021, 10:40 PM

There can't be more than one reason? When was that deal negotiated? I'll bet it was years ago.

Puppycow · 20th September 2021, 02:58 AM

Originally Posted by arthwollipot

There can't be more than one reason? When was that deal negotiated? I'll bet it was years ago.

To expand on that a bit, I think it's because not all rockets are capable of carrying this kind of payload to the destination. It isn't going to LEO, like the Hubble, but to a Lagrange point which is much farther out in space.

The Europeans had a rocket that could do it at a time when the Americans did not.

RecoveringYuppy · 20th September 2021, 06:59 AM

Originally Posted by jadebox

Again, the reason the telescope is being launched on an Ariane is that NASA negotiated a deal in exchange for observation time using the telescope.

OK. Why did you feel the need to repeat that? Are we missing something?

You seem to be implying that because they charged a price for the service that there wasn't a reason we chose their service, which doesn't really make sense.

theprestige · 20th September 2021, 07:02 AM

It just seems like a weird reason to me. Wouldn't everyone be getting time on the scope anyway?

Segnosaur · 20th September 2021, 07:22 AM

Quote:

Again, the reason the telescope is being launched on an Ariane is that NASA negotiated a deal in exchange for observation time using the telescope.

That makes sense from a financial perspective. (Share the cost/share the benefit). But, they could have also negotiated a deal that said "We'll pay SpaceX/NASA/etc. to launch in exchange for observation time"

Quote:

To expand on that a bit, I think it's because not all rockets are capable of carrying this kind of payload to the destination. It isn't going to LEO, like the Hubble, but to a Lagrange point which is much farther out in space.

The Europeans had a rocket that could do it at a time when the Americans did not.

This also makes sense. (I'm surprised that the Americans didn't have any sort of heavy-lift capability at the time, but I guess that sort of thing happens.)

But then, there is still the question: Why launch from French Guiana, instead of launching the European rocket from Kennedy Space Center. (Note: My concern is mostly about the risk of transporting the telescope overseas. Even if the risks may be minimal, the telescope was a huge investment in resources. If it were me I would want to eliminate anything that could jeopardize it.)

RecoveringYuppy · 20th September 2021, 07:46 AM

Originally Posted by Segnosaur

But then, there is still the question: Why launch from French Guiana, instead of launching the European rocket from Kennedy Space Center.

Pretty sure rockets can't be moved around that easily. KSC wouldn't be equipped to launch an Ariane.

Puppycow · 20th September 2021, 07:50 AM

According to Wikipedia, the parameters of this agreement seem to have been agreed to all the way back in 2007.

https://en.wikipedia.org/wiki/James_...pe#Partnership

Quote:

NASA, ESA and CSA have collaborated on the telescope since 1996. ESA's participation in construction and launch was approved by its members in 2003 and an agreement was signed between ESA and NASA in 2007. In exchange for full partnership, representation and access to the observatory for its astronomers, ESA is providing the NIRSpec instrument, the Optical Bench Assembly of the MIRI instrument, an Ariane 5 ECA launcher, and manpower to support operations.[78][124] The CSA will provide the Fine Guidance Sensor and the Near-Infrared Imager Slitless Spectrograph plus manpower to support operations.[125]

Quote:

But then, there is still the question: Why launch from French Guiana, instead of launching the European rocket from Kennedy Space Center. (Note: My concern is mostly about the risk of transporting the telescope overseas. Even if the risks may be minimal, the telescope was a huge investment in resources. If it were me I would want to eliminate anything that could jeopardize it.)

Wouldn't it be even more difficult and possibly risky to transport the European rocket to Kennedy Space Center? Just BTW, if the plan was set in stone back in 2007, there may have been other considerations at the time. It was probably seen as the most viable available rocket vehicle at the time which met all of the requirements.

jadebox · 20th September 2021, 07:58 AM

Originally Posted by RecoveringYuppy

You seem to be implying that because they charged a price for the service that there wasn't a reason we chose their service, which doesn't really make sense.

Huh?

The main reason that the ESA is launching the telescope is that they agreed to do so in exchange for observation time using the telescope. ULA could have launched it using an Atlas or Delta rocket, but they would have charged NASA for the launch. SpaceX wasn't an option when the launch was negotiated.

RecoveringYuppy · 20th September 2021, 08:21 AM

Yeah, you've said some of that multiple times. Just wondering why you are repeating it. Not important.

Ziggurat · 20th September 2021, 09:40 AM

Originally Posted by Segnosaur

Anyone know why it is being launched from French Guiana and not from KSC?

Since it's going up on a European Space Agency rocket, why would it launch from a NASA facility instead of from a European Space Agency facility? I imagine that an orbital rocket launch requires a fair amount of ground support specific to the kind of rocket you're launching. I doubt KSC has that stuff already for an Ariane rocket, whereas Arianes launch from the Guiana Space Center all the time. Importing that equipment to KSC for one launch likely doesn't make any sense.

theprestige · 20th September 2021, 09:55 AM

Now I want a documentary on the transport cradle(s) for the scope and its major subassemblies. The engineering on that thing must be super intense. Especially if they're confident it can keep the scope safe during a voyage through the entire range of possible Atlantic weather.

Ziggurat · 20th September 2021, 10:09 AM

Originally Posted by theprestige

Now I want a documentary on the transport cradle(s) for the scope and its major subassemblies. The engineering on that thing must be super intense. Especially if they're confident it can keep the scope safe during a voyage through the entire range of possible Atlantic weather.

I doubt it's going to have more stress on it during transport to the launch facility than it will have during launch. But yes, engineering a complex satellite to withstand launch forces is a very non-trivial endeavor. It isn't just about the g-forces of launch either, there can also be quite a bit of vibration.

Puppycow · 19th October 2021, 03:34 AM

$10bn James Webb Space Telescope unpacked in Kourou

One step closer.

Hey, at least the boat it was shipped on wasn’t attacked by pirates or Kaiju.

December 18th is the day, now 2 months away, if everything goes according to plan.

3point14 · 19th October 2021, 06:06 AM

Forgive my ignorance. And this is probably in the thread somewhere.

How long does it take to get on station and then start working? When can we expect pictures of little green men?

3rd June 2021, 08:58 PM	#81
Pixel42 Schrödinger's cat Join Date: May 2004 Location: Malmesbury, UK Posts: 14,813	I think of pure scientific research as akin to music or art - we do these things to enrich our minds, not our material welfare. It's what makes us civilised, makes us different to the animals from which we evolved. Any practical benefits which eventually emerge are just an added bonus.
	__________________ "If you trust in yourself ... and believe in your dreams ... and follow your star ... you'll still get beaten by people who spent their time working hard and learning things" - Terry Pratchett

3rd June 2021, 10:18 PM	#82
slyjoe Illuminator Join Date: Mar 2007 Location: Near Harmonica Virgins, AZ Posts: 3,255	Originally Posted by Pixel42 I think of pure scientific research as akin to music or art - we do these things to enrich our minds, not our material welfare. It's what makes us civilised, makes us different to the animals from which we evolved. Any practical benefits which eventually emerge are just an added bonus. And, don't forget the other difference, we use cutlery.
	__________________ "You have done nothing to demonstrate an understanding of scientific methodology or modern skepticism, both of which are, by necessity, driven by the facts and evidence, not by preconceptions, and both of which are strengthened by, and rely upon, change." - Arkan Wolfshade

4th June 2021, 03:50 AM	#83
Ziggurat Penultimate Amazing Join Date: Jun 2003 Posts: 51,990	Originally Posted by Pixel42 I think of pure scientific research as akin to music or art - we do these things to enrich our minds, not our material welfare. It's what makes us civilised, makes us different to the animals from which we evolved. Any practical benefits which eventually emerge are just an added bonus. I think it was Feynman who said physics is like sex: it has practical results, but that’s not why we do it.
	__________________ "As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law

4th June 2021, 04:25 AM	#84
erwinl Illuminator Join Date: Sep 2008 Posts: 3,265	Originally Posted by Ziggurat Sure, but they don't have the budget for two of these. And with the budget they do have, any telescope they could build two of wouldn't be as good. And they'd rather have less time on a better telescope than more time on inferior ones. ETA: I can see a use case for multiple identical space telescopes, though. With radio astronomy, building multiple telescopes to form a giant array allows you to get vastly better diffraction limits on your signal than you can with a single telescope. Is that possible for Visible Light telescopes as well? Or it it not practical enough for that frequency band of the spectrum?
erwinl Illuminator Join Date: Sep 2008 Posts: 3,265	__________________ Bow before your king Member of the "Zombie Misheard Lyrics Support Group"

4th June 2021, 04:38 AM	#85
Belz... Fiend God Join Date: Oct 2005 Location: In a post-fact world Posts: 96,875	Originally Posted by Samson I cant imagine any reason that moving this telescope would be unplanned for. ...what?
	__________________ Master of the Shining Darkness "My views are nonsense. So what?" - BobTheCoward

4th June 2021, 04:39 AM	#86
Belz... Fiend God Join Date: Oct 2005 Location: In a post-fact world Posts: 96,875	Originally Posted by jonesdave116 Yep. Given that it will be at at the L2 point, fixing it is not going to be easy. Or cheap. More like too hard to even attempt. A lot of money down the drain if this fails. Maybe they should make wider rocket heads, instead.
	__________________ Master of the Shining Darkness "My views are nonsense. So what?" - BobTheCoward Last edited by Belz...; 4th June 2021 at 04:45 AM.

4th June 2021, 04:40 AM	#87
Belz... Fiend God Join Date: Oct 2005 Location: In a post-fact world Posts: 96,875	Originally Posted by Samson Again, 10 billion is now small change for Gate Musk Bezos Zukerberg Buffet Apple etc. Er... no it isn't. Quote: A good that includes avoiding another Chuxilliub What do asteroids have to do with the telescope???
	__________________ Master of the Shining Darkness "My views are nonsense. So what?" - BobTheCoward

4th June 2021, 05:00 AM	#88
Samson Penultimate Amazing Join Date: Oct 2013 Posts: 10,024	Originally Posted by Belz... Er... no it isn't. What do asteroids have to do with the telescope??? I bet T rex would wish even a suboptimal device like James Webb had warned him. (Honey i shrunk the kids)

4th June 2021, 05:27 AM	#89
Belz... Fiend God Join Date: Oct 2005 Location: In a post-fact world Posts: 96,875	Originally Posted by Samson I bet T rex would wish even a suboptimal device like James Webb had warned him. (Honey i shrunk the kids) Are you high right now? I can't make heads or tails of your posts.
	__________________ Master of the Shining Darkness "My views are nonsense. So what?" - BobTheCoward

4th June 2021, 05:32 AM	#90
Ziggurat Penultimate Amazing Join Date: Jun 2003 Posts: 51,990	Originally Posted by erwinl Is that possible for Visible Light telescopes as well? Or it it not practical enough for that frequency band of the spectrum? I don’t think we can do it for optical band. You need to be able to accurately time the phase of the signal between your different detectors, and I don’t think we really have that capability for visible light in the same way.
	__________________ "As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law

4th June 2021, 06:50 AM	#91
Ziggurat Penultimate Amazing Join Date: Jun 2003 Posts: 51,990	Originally Posted by erwinl Is that possible for Visible Light telescopes as well? Or it it not practical enough for that frequency band of the spectrum? The other thing is that using multiple telescopes as a giant interferometer only helps overcome the diffraction limit on angular resolution, it doesn't really amplify the signal strength. So if you've got a bright source that provides plenty of signal and you just need better angular resolution, using this can help a lot. If you're limited on signal intensity, this won't help much. But it turns out I was wrong, there are actually some optical interferometer telescopes, for example: https://en.wikipedia.org/wiki/Navy_P...Interferometer But in general, it's not used as much for optical as radio. For one, I think it's easier with radio. Two, radio benefits more, since the diffraction limit is much worse for a single radio telescope dish than for an optical telescope. And three, optical telescopes are often signal limited anyways, so you need big dishes anyways, and that helps with the diffraction limit as a side effect.
	__________________ "As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law

4th June 2021, 07:15 AM	#92
erwinl Illuminator Join Date: Sep 2008 Posts: 3,265	Originally Posted by Ziggurat The other thing is that using multiple telescopes as a giant interferometer only helps overcome the diffraction limit on angular resolution, it doesn't really amplify the signal strength. So if you've got a bright source that provides plenty of signal and you just need better angular resolution, using this can help a lot. If you're limited on signal intensity, this won't help much. But it turns out I was wrong, there are actually some optical interferometer telescopes, for example: https://en.wikipedia.org/wiki/Navy_P...Interferometer But in general, it's not used as much for optical as radio. For one, I think it's easier with radio. Two, radio benefits more, since the diffraction limit is much worse for a single radio telescope dish than for an optical telescope. And three, optical telescopes are often signal limited anyways, so you need big dishes anyways, and that helps with the diffraction limit as a side effect. Thanks! A bit as I suspected. But I had no idea concerning present capabilities and/or benefits so I thought, I’d ask.
erwinl Illuminator Join Date: Sep 2008 Posts: 3,265	__________________ Bow before your king Member of the "Zombie Misheard Lyrics Support Group"

4th June 2021, 08:22 AM	#93
RecoveringYuppy Penultimate Amazing Join Date: Nov 2006 Posts: 13,591	Originally Posted by erwinl Is that possible for Visible Light telescopes as well? Or it it not practical enough for that frequency band of the spectrum? It's starting to be practical. ETA: helps if I actually add the link, and I see Ziggurat already posted on this issue. https://www.nature.com/articles/464820a
	Last edited by RecoveringYuppy; 4th June 2021 at 08:24 AM.

4th June 2021, 12:46 PM	#94
Blue Mountain Resident Skeptical Hobbit Join Date: Jul 2005 Location: Waging war on woo-woo in Winnipeg Posts: 7,032	Originally Posted by Belz... Er... no it isn't. What do asteroids have to do with the telescope??? Originally Posted by Samson I bet T rex would wish even a suboptimal device like James Webb had warned him. (Honey i shrunk the kids) I'm not sure how the "Honey, I Shrunk the Kids" remark figures into Samson's post, but he's alluding to programs such as NASA's Near-Earth Object Observations Program, which scans the sky looking for things on a collision course with Earth. Of greatest concern something like the object that caused the Chicxulub crater and also wiped out the dinosaurs, which is what Samson was referring to when he mentioned T. Rex. As humans we're also interested in smaller objects like the one that caused the Tunguska event back in 1908: imagine the carnage it could have caused had it occurred over a populated area instead of remote Siberia. See also the Chelyabinsk meteor, and other modern impact events. I'm not sure the JWST will help with near Earth observation programs, but we do have Earth based telescopes that are continually searching for potential impact objects.
	__________________ The social illusion reigns to-day upon all the heaped-up ruins of the past, and to it belongs the future. The masses have never thirsted after truth. They turn aside from evidence that is not to their taste, preferring to deify error, if error seduce them. Gustav Le Bon, The Crowd, 1895 (from the French)

4th June 2021, 01:11 PM	#95
Belz... Fiend God Join Date: Oct 2005 Location: In a post-fact world Posts: 96,875	Originally Posted by Blue Mountain I'm not sure how the "Honey, I Shrunk the Kids" remark figures into Samson's post, but he's alluding to programs such as NASA's Near-Earth Object Observations Program, which scans the sky looking for things on a collision course with Earth. Of greatest concern something like the object that caused the Chicxulub crater and also wiped out the dinosaurs, which is what Samson was referring to when he mentioned T. Rex. As humans we're also interested in smaller objects like the one that caused the Tunguska event back in 1908: imagine the carnage it could have caused had it occurred over a populated area instead of remote Siberia. See also the Chelyabinsk meteor, and other modern impact events. I'm not sure the JWST will help with near Earth observation programs, but we do have Earth based telescopes that are continually searching for potential impact objects. It won't. It has nothing to do with it, which is why samson's post is puzzling. That's what I would say if samson's posts usually made sense.
	__________________ Master of the Shining Darkness "My views are nonsense. So what?" - BobTheCoward

4th June 2021, 11:04 PM	#96
Roboramma Penultimate Amazing Join Date: Feb 2005 Location: Shanghai Posts: 15,060	Originally Posted by Belz... It won't. It has nothing to do with it, which is why samson's post is puzzling. That's what I would say if samson's posts usually made sense. Exactly. And I actually pointed this out to Samson earlier, so it's weird that he keeps bringing it up. I suppose it's possible that if a potential problem asteroid or comet was noticed with some other instrument, JWST could be pointed in that direction and potentially give a more accurate measurement of its orbit. I'm not sure if JWST would be better than other telescopes for that job, or how much we could potentially gain from it in that use. But, as you say, in general James Webb isn't involved in cataloging asteroids, so it doesn't seem to have much to do with the issues of potential impacts.
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5th June 2021, 08:03 AM	#97
RecoveringYuppy Penultimate Amazing Join Date: Nov 2006 Posts: 13,591	Originally Posted by Roboramma Exactly. And I actually pointed this out to Samson earlier, so it's weird that he keeps bringing it up. I suppose it's possible that if a potential problem asteroid or comet was noticed with some other instrument, JWST could be pointed in that direction and potentially give a more accurate measurement of its orbit. I'm not sure if JWST would be better than other telescopes for that job, or how much we could potentially gain from it in that use. But, as you say, in general James Webb isn't involved in cataloging asteroids, so it doesn't seem to have much to do with the issues of potential impacts. Radar is the best way to accurately track asteroids. But the world is a bit short on that now that Arecibo is gone.

17th September 2021, 04:58 AM	#98
Puppycow Penultimate Amazing Join Date: Jan 2003 Location: Yokohama, Japan Posts: 27,262	Einstein ring captured by Hubble Two galaxies with a distant quasar behind them. Linky And, the JWST now has an "official" launch date of December 18th: https://www.bbc.com/news/science-environment-58498676 Quote: The $10bn James Webb Space Telescope is expected to launch on 18 December. Yes, countless targeted lift-offs have come and gone in the past, but this one has a reality to it that the others didn't: the successor observatory to Hubble is now actually built. All that is required is to ship the finished telescope to French Guiana, put it on the top of an Ariane rocket, light the engines and stand well back.
	__________________ A fool thinks himself to be wise, but a wise man knows himself to be a fool. William Shakespeare

17th September 2021, 11:14 PM	#99
a_unique_person Director of Hatcheries and Conditioning Join Date: Jul 2002 Location: Waiting for the pod bay door to open. Posts: 44,460	Fingers crossed.
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18th September 2021, 06:27 AM	#100
Segnosaur Penultimate Amazing Join Date: Jan 2002 Location: Canada, eh? Posts: 18,955	Anyone know why it is being launched from French Guiana and not from KSC? (I know that there is European involvement in the project, but since the telescope was assembled in California, transporting it overseas seems like an unnecessary risk/expense.) Sent from my LM-X320 using Tapatalk
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18th September 2021, 06:49 AM	#101
jadebox Master Poster Join Date: Sep 2004 Location: USA Posts: 2,261	Originally Posted by Segnosaur Anyone know why it is being launched from French Guiana and not from KSC? (I know that there is European involvement in the project, but since the telescope was assembled in California, transporting it overseas seems like an unnecessary risk/expense.) Sent from my LM-X320 using Tapatalk The ESA offered to launch the telescope in exchange for time using the telescope.

18th September 2021, 10:31 AM	#102
Garrison Philosopher Join Date: Sep 2011 Location: UK Posts: 5,837	If it was delayed much longer it could have been launching on Starship.
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18th September 2021, 05:36 PM	#103
Pope130 Illuminator Join Date: Sep 2005 Location: Oregon Posts: 3,583	Originally Posted by Segnosaur Anyone know why it is being launched from French Guiana and not from KSC? (I know that there is European involvement in the project, but since the telescope was assembled in California, transporting it overseas seems like an unnecessary risk/expense.) Sent from my LM-X320 using Tapatalk One factor is that French Guiana is closer to the equator, getting more use from the Earth's rotational speed.

18th September 2021, 06:32 PM	#104
RecoveringYuppy Penultimate Amazing Join Date: Nov 2006 Posts: 13,591	Originally Posted by Pope130 One factor is that French Guiana is closer to the equator, getting more use from the Earth's rotational speed. That's not much of a gain even for things headed toward equatorial GEO. Won't that gain come at the cost of having to change the orbital plane later? Not sure what the exact demands are of the final orbit.

19th September 2021, 09:10 PM	#105
arthwollipot Observer of Phenomena Pronouns: he/him Join Date: Feb 2005 Location: Ngunnawal Country Posts: 77,485	There's also the issue that the contracts have been signed for ages. It could have gone up on a SpaceX Falcon Heavy, but instead it's going up on an older Ariane.
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19th September 2021, 09:31 PM	#106
jadebox Master Poster Join Date: Sep 2004 Location: USA Posts: 2,261	Again, the reason the telescope is being launched on an Ariane is that NASA negotiated a deal in exchange for observation time using the telescope. Quote: Why is NASA's most expensive scientific instrument ever launching on a European rocket? Because the European Space Agency is conducting the launch for NASA in return for a share of observation time using the infrared telescope. -- https://arstechnica.com/science/2021...e-launch-date/

19th September 2021, 10:40 PM	#107
arthwollipot Observer of Phenomena Pronouns: he/him Join Date: Feb 2005 Location: Ngunnawal Country Posts: 77,485	There can't be more than one reason? When was that deal negotiated? I'll bet it was years ago.
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20th September 2021, 02:58 AM	#108
Puppycow Penultimate Amazing Join Date: Jan 2003 Location: Yokohama, Japan Posts: 27,262	Originally Posted by arthwollipot There can't be more than one reason? When was that deal negotiated? I'll bet it was years ago. To expand on that a bit, I think it's because not all rockets are capable of carrying this kind of payload to the destination. It isn't going to LEO, like the Hubble, but to a Lagrange point which is much farther out in space. The Europeans had a rocket that could do it at a time when the Americans did not.
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20th September 2021, 06:59 AM	#109
RecoveringYuppy Penultimate Amazing Join Date: Nov 2006 Posts: 13,591	Originally Posted by jadebox Again, the reason the telescope is being launched on an Ariane is that NASA negotiated a deal in exchange for observation time using the telescope. OK. Why did you feel the need to repeat that? Are we missing something? You seem to be implying that because they charged a price for the service that there wasn't a reason we chose their service, which doesn't really make sense.
	Last edited by RecoveringYuppy; 20th September 2021 at 07:04 AM.

20th September 2021, 07:02 AM	#110
theprestige Penultimate Amazing Join Date: Aug 2007 Location: The Antimemetics Division Posts: 60,326	It just seems like a weird reason to me. Wouldn't everyone be getting time on the scope anyway?
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20th September 2021, 07:22 AM	#111
Segnosaur Penultimate Amazing Join Date: Jan 2002 Location: Canada, eh? Posts: 18,955	Quote: Again, the reason the telescope is being launched on an Ariane is that NASA negotiated a deal in exchange for observation time using the telescope. That makes sense from a financial perspective. (Share the cost/share the benefit). But, they could have also negotiated a deal that said "We'll pay SpaceX/NASA/etc. to launch in exchange for observation time" Quote: To expand on that a bit, I think it's because not all rockets are capable of carrying this kind of payload to the destination. It isn't going to LEO, like the Hubble, but to a Lagrange point which is much farther out in space. The Europeans had a rocket that could do it at a time when the Americans did not. This also makes sense. (I'm surprised that the Americans didn't have any sort of heavy-lift capability at the time, but I guess that sort of thing happens.) But then, there is still the question: Why launch from French Guiana, instead of launching the European rocket from Kennedy Space Center. (Note: My concern is mostly about the risk of transporting the telescope overseas. Even if the risks may be minimal, the telescope was a huge investment in resources. If it were me I would want to eliminate anything that could jeopardize it.)
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20th September 2021, 07:46 AM	#112
RecoveringYuppy Penultimate Amazing Join Date: Nov 2006 Posts: 13,591	Originally Posted by Segnosaur But then, there is still the question: Why launch from French Guiana, instead of launching the European rocket from Kennedy Space Center. Pretty sure rockets can't be moved around that easily. KSC wouldn't be equipped to launch an Ariane.

20th September 2021, 07:50 AM	#113
Puppycow Penultimate Amazing Join Date: Jan 2003 Location: Yokohama, Japan Posts: 27,262	According to Wikipedia, the parameters of this agreement seem to have been agreed to all the way back in 2007. https://en.wikipedia.org/wiki/James_...pe#Partnership Quote: NASA, ESA and CSA have collaborated on the telescope since 1996. ESA's participation in construction and launch was approved by its members in 2003 and an agreement was signed between ESA and NASA in 2007. In exchange for full partnership, representation and access to the observatory for its astronomers, ESA is providing the NIRSpec instrument, the Optical Bench Assembly of the MIRI instrument, an Ariane 5 ECA launcher, and manpower to support operations.[78][124] The CSA will provide the Fine Guidance Sensor and the Near-Infrared Imager Slitless Spectrograph plus manpower to support operations.[125] Quote: But then, there is still the question: Why launch from French Guiana, instead of launching the European rocket from Kennedy Space Center. (Note: My concern is mostly about the risk of transporting the telescope overseas. Even if the risks may be minimal, the telescope was a huge investment in resources. If it were me I would want to eliminate anything that could jeopardize it.) Wouldn't it be even more difficult and possibly risky to transport the European rocket to Kennedy Space Center? Just BTW, if the plan was set in stone back in 2007, there may have been other considerations at the time. It was probably seen as the most viable available rocket vehicle at the time which met all of the requirements.
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20th September 2021, 07:58 AM	#114
jadebox Master Poster Join Date: Sep 2004 Location: USA Posts: 2,261	Originally Posted by RecoveringYuppy You seem to be implying that because they charged a price for the service that there wasn't a reason we chose their service, which doesn't really make sense. Huh? The main reason that the ESA is launching the telescope is that they agreed to do so in exchange for observation time using the telescope. ULA could have launched it using an Atlas or Delta rocket, but they would have charged NASA for the launch. SpaceX wasn't an option when the launch was negotiated.

20th September 2021, 08:21 AM	#115
RecoveringYuppy Penultimate Amazing Join Date: Nov 2006 Posts: 13,591	Yeah, you've said some of that multiple times. Just wondering why you are repeating it. Not important.