James Webb Telescope Updates

[Ophiolite]

That reminds me of that persistent sci-fi movie trope - where the spaceship has to navigate through or hide in an asteroid belt or cloud and they're dodging between the boulders like a video game - when, in practice, the asteroids would probably be too far apart to even see more than an occasional speck in the distance...

The inter-object distances, but not their size, are probably within an order of magnitude or so for particles in one ore more of Saturn's rings. It occurs to me that an interesting book (or, in today's world - YouTube video series) would be a presentation and refutation of the many ghastly and persistent errors that infest SF films.

 

[Halbhh]

...many ghastly and persistent errors that infest SF films.

True dat.

I was less bothered than usual by the somewhat more tolerable pretend physics of The Expanse on Amazon Prime. At least the objects traveling in space have momentum that doesn't suddenly cease to exist, and also many instances things moving through space vacuum are not noisy, lol.... that's not to say it's always perfect (they seemed to have decided that having at least a little spacecraft noise outside in space is still needed for viewers (from camera eye out in space away from craft), , but it is usually easier to follow the story without getting disgusted with the physics than I'm used to seeing. After a time I decided to imagine there was a microphone attached to the craft, even though the camera is a ways off in space, lol.....

 

[FrumiousBandersnatch]

True dat.

I was less bothered than usual by the somewhat more tolerable pretend physics of The Expanse on Amazon Prime. At least the objects traveling in space have momentum that doesn't suddenly cease to exist, and also many instances things moving through space vacuum are not noisy, lol.... that's not to say it's always perfect (they seemed to have decided that having at least a little spacecraft noise outside in space is still needed for viewers (from camera eye out in space away from craft), , but it is usually easier to follow the story without getting disgusted with the physics than I'm used to seeing. After a time I decided to imagine there was a microphone attached to the craft, even though the camera is a ways off in space, lol.....

I still remember how shocking the EVAs were in Kubrick's '2001 - A Space Odyssey' with only the sound of the astronaut's breathing. It was made when only a handful of men had gone into space - and there had been even fewer EVAs.

 

[Ophiolite]

I still remember how shocking the EVAs were in Kubrick's '2001 - A Space Odyssey' with only the sound of the astronaut's breathing.

Excellent point. I can still here the rhythym and tone of that breathing in my head,heightening the tension of the scene. A tribute to Kubrick's artistry and genius.

 

[Opdrey]

Yes; I only hope that what is out there in orbit in 2087 is not a vast field of satellite debris blocking access to space for both physical launches and astronomical observations...

I had just read about this recently. I had never really thought about it but it makes sense...we might effectively trap ourselves on the planet. And then all these private companies like SpaceX launching zillions of little satellites (the ones that don't get fried immediately by solar storms) so we can have internet everywhere or so that individual companies can have their own satellite nets. Ugh.

 

[FrumiousBandersnatch]

I had just read about this recently. I had never really thought about it but it makes sense...we might effectively trap ourselves on the planet. And then all these private companies like SpaceX launching zillions of little satellites (the ones that don't get fried immediately by solar storms) so we can have internet everywhere or so that individual companies can have their own satellite nets. Ugh.

Yes, it's a classic demonstration of self-defeating technology. We're going to have to send up more satellites to clear all the junk and dead ones, then those clean-up satellites will fight it out to 'Last Satellite Orbiting'. The survivor will be so effective it'll immediately de-orbit anything else we send up there...

 

[Halbhh]

Aligned.

Hearing that it's a sharp "as can be" for a telescope of this size by the laws of physics.



That's exciting. More later.

 

[Halbhh]

After meeting the major milestone of aligning the telescope to NIRCam, the Webb team is starting to extend the telescope alignment to the guider (the Fine Guidance Sensor, or FGS) and the other three science instruments. This six-week-long process is called multi-instrument multi-field (MIMF) alignment.

When a ground-based telescope switches between cameras, sometimes the instrument is physically taken off the telescope, and a new one is installed during the daytime when the telescope is not in use. If the other instrument is already on the telescope, mechanisms are in place to move part of the telescope’s optics (known as a pick-off mirror) into the field of view.

On space telescopes like Webb, all the cameras see the sky at the same time; to switch a target from one camera to another, we repoint the telescope to put the target into the field of view of the other instrument.

After MIMF, Webb’s telescope will provide a good focus and sharp images in all the instruments. ...
James Webb Space Telescope

 

[sjastro]

After meeting the major milestone of aligning the telescope to NIRCam, the Webb team is starting to extend the telescope alignment to the guider (the Fine Guidance Sensor, or FGS) and the other three science instruments. This six-week-long process is called multi-instrument multi-field (MIMF) alignment.

When a ground-based telescope switches between cameras, sometimes the instrument is physically taken off the telescope, and a new one is installed during the daytime when the telescope is not in use. If the other instrument is already on the telescope, mechanisms are in place to move part of the telescope’s optics (known as a pick-off mirror) into the field of view.

On space telescopes like Webb, all the cameras see the sky at the same time; to switch a target from one camera to another, we repoint the telescope to put the target into the field of view of the other instrument.

After MIMF, Webb’s telescope will provide a good focus and sharp images in all the instruments. ...
James Webb Space Telescope

Here is a fun fact.
Despite Webb having a mirror diameter 2.7X greater than Hubble resulting in having 6X the light gathering power of Hubble, it will be no better than Hubble in terms of resolving fine detail.
For example a binary star with angular separation Δθ can be separated into individual stars by a telescope according to the formula.

Despite having a large mirror the resolving power of Webb is reduced as it is designed to image in longer infrared wavelengths.

 

[Halbhh]

Here is a fun fact.
Despite Webb having a mirror diameter 2.7X greater than Hubble resulting in having 6X the light gathering power of Hubble, it will be no better than Hubble in terms of resolving fine detail.
For example a binary star with angular separation Δθ can be separated into individual stars by a telescope according to the formula.

Despite having a large mirror the resolving power of Webb is reduced as it is designed to image in longer infrared wavelengths.

Yes, it's interesting the sharpness of stuff to our eyes in the pictures will be in the same neighborhood. I'm looking forward to seeing what's visible in infrared at better resolution than before, like stuff behind dust, which includes interesting regions such as perhaps more detail of stellar birth maybe, and/or planet formation in places. Also, the extremely distant stuff that is redshifted from higher frequencies down into the Webb range. And another thing that will be interesting is getting infrared range light that passes through an exoplanet atmosphere.

 

[Halbhh]

Instrument commissioning is ongoing. At the end of April the alignment was completed. The instrument commissioning was expected to take about 2 months.

But get this

"The alignment of the telescope across all of Webb’s instruments can be seen in a series of images that captures the observatory’s full field of view.

(Click to enlarge!, and then after looking read the paragraph below the images)

"The optical performance of the telescope continues to be better than the engineering team’s most optimistic predictions. Webb’s mirrors are now directing fully focused light collected from space down into each instrument, and each instrument is successfully capturing images with the light being delivered to them. The image quality delivered to all instruments is “diffraction-limited,” meaning that the fineness of detail that can be seen is as good as physically possible given the size of the telescope. From this point forward the only changes to the mirrors will be very small, periodic adjustments to the primary mirror segments."

NASA’s Webb In Full Focus, Ready for Instrument Commissioning – James Webb Space Telescope

 

[Halbhh]

Here's a fun example of what that longer wavelength might mean for a 'deep field' type image, since we will see further redshifted -- thus more distant objects -- than Hubble, but at similar sharpness:

James Webb Space Telescope: The scientific mysteries no other observatory could unravel

Here is a fun fact.
Despite Webb having a mirror diameter 2.7X greater than Hubble resulting in having 6X the light gathering power of Hubble, it will be no better than Hubble in terms of resolving fine detail.
For example a binary star with angular separation Δθ can be separated into individual stars by a telescope according to the formula.

Despite having a large mirror the resolving power of Webb is reduced as it is designed to image in longer infrared wavelengths.

 

[Halbhh]

Ah, we still have to wait till July 12th for the fun first official photo big splash.

June 23, 2022
The Webb team has now approved 10 out of 17 science instrument modes; since last week we added (14) MIRI imaging, (2) NIRCam wide-field slitless spectroscopy, and our final NIRISS mode, (10) single-object slitless spectroscopy. As we ramp down the final commissioning activities, some openings in the schedule have appeared. The team has started to take some of the first science data, getting it ready to release starting July 12, 2022, which will mark the official end of commissioning Webb and the start of routine science operations.
James Webb Space Telescope

 

[Halbhh]

Here's a great article I saw yesterday, with more exciting detail imo, about some observing goals:

https://phys.org/news/2022-06-nasa-webb-uncover-riches-early.html

Here's one that is really interesting to me:

For decades, telescopes have helped us capture light from galaxies that formed as far back as 400 million years after the big bang—incredibly early in the context of the universe's 13.8-billion-year history. But what were galaxies like that existed even earlier, when the universe was semi-transparent at the beginning of a period known as the Era of Reionization? NASA's next flagship observatory, the James Webb Space Telescope, is poised to add new riches to our wealth of knowledge not only by capturing images from galaxies that existed as early as the first few hundred million years after the big bang, but also by giving us detailed data known as spectra. With Webb's observations, researchers will be able to tell us about the makeup and composition of individual galaxies in the early universe for the first time.

Never yet observed even earlier-in-time galaxies. The early galaxies we have seen in recent years surprised us already, just for forming sooner than had been expected, showing previous ideas about when galaxies first formed were incorrect.

 

[sjastro]

Images and spectra are starting to come out but subject to the media ban which is lifted July 12th.
In the meantime NASA and ESA have released the mid-IR spectrum of the galaxy NGC 6552 showing the extraordinary resolution of Webb when compared to Spitzer.

This portion of the MIRI MRS wavelength range shows engineering calibration data obtained of the Seyfert galaxy NGC 6552 (red line) in the constellation Draco. The strong emission feature is due to molecular hydrogen, with an additional weaker feature nearby. The blue line shows a lower spectral resolution Spitzer IRS spectrum of a similar galaxy for comparison. The Webb test observations were obtained to establish the wavelength calibration of the spectrograph. Credit: NASA, ESA, and the MIRI Consortium.

 

[sjastro]

Latest status on the commissioning of instruments on the JWST.

​

Dr Becky is excluded from information sharing during the media blackout as she might blab to the public.

 

[Hans Blaster]

Latest status on the commissioning of instruments on the JWST.

Only the coronograph mode left to finish. All 16 other modes are operational and available for data acquisition. Observations are underway...

 

[sjastro]

On July 12th NASA will reveal the deepest field image of the universe ever taken.
Astronomers viewing images not yet released to the public have reacted in various ways such as this.
https://scitechdaily.com/astronomer...telescope-images-almost-brought-him-to-tears/

 

[sjastro]

NASA release a rough around the edges teaser image.

The image has some "rough-around-the-edges" qualities, NASA said in a statement, but is still "among the deepest images of the universe ever taken" and offers a "tantalizing glimpse" at what will be revealed in the coming weeks, months, and years.

 

[SelfSim]

NASA release a rough around the edges teaser image.

Mind blowing!
There's too much stuff! (It just aint natural, man!)