JWST: On July 12, we'll see the universe like never before

[Glenn Newell]

FYI:

https://www.zdnet.com/article/on-july-12-well-see-the-universe-like-never-before/

On July 12, the world will have a new perspective of the universe, when the James Webb Space Telescope (JWST) mission releases its first set of full-color images as well as spectroscopic data. One of the photos to be released is the deepest image of our universe that has ever been taken, NASA Administrator Bill Nelson told reporters on Wednesday.

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The photos that will be released were chosen for their spectacular color imagery, NASA said

Wednesday, as well as to demonstrate the breadth of science that the JWST is supporting. 

"We're only beginning to understand what Webb can and will do," Nelson said. "It's going to explore objects in the solar system and atmospheres of exoplanets orbiting other stars -- giving us clues as to whether their atmospheres are similar to our own. It may answer some questions that we have. Where do we come from? What more is out there? Who are we?"

Each image released next month will reveal different aspects of the infrared universe in unprecedented detail and sensitivity, scientists said Wednesday during a news conference. 

Along with the deepest infrared view of the cosmos to date, the images also will show how galaxies interact and grow. Webb can reveal, for example, how cataclysmic collisions drive the process of star formation, with new, young stars emerging from their natal cloud of gas and dust. The telescope's images could also show dying stars seeding the galaxy with new elements and new dust that may one day become part of new planetary systems. 

The images released on July 12 also will include the first spectrum of an exoplanet. NASA has confirmed the existence of more than 5,000 planets beyond our solar system, and looking at the vibrational spectrum of one could help us understand what molecules exist in its atmosphere -- and whether the exoplanet could potentially support life. 

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[Bruce Braunstein]

This is an amazing moment….

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Bruce B.
BBRA...@gmail.com

[Gary Hethcoat]

All the more interesting because we're not sure what to expect.  At least I'm not :-)

Gary

Gary Hethcoat
gary.h...@gmail.com

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[Gary Hethcoat]

This Google search turned up some comparison images that might give us an idea what to expect.  I'm just not very familiar with infrared astrophotography, maybe some of you are familiar.

Gary

Gary Hethcoat
gary.h...@gmail.com

[Nikola Nikolov]

Thank you, Glenn!

First data from JWST will be monochrome fit files. :)  Just like our mono CMOS cameras.

However, the information captured in these raw fits is the biggest value. This is where the science begins.

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[Paolo Barettoni]

Of course Nikola, You are right about the monochrome images, but I suspect that Nasa will come out with some sort of false coloring, just to appeal the wide public and increase the WOW factor...

I'm accepting bet....

Paolo

[ian clements]

I’m curious speaking of false color. With the subject matter, do they use Hubble’s pallet or have they developed a newer “JWST” pallet?

On Jul 3, 2022, at 13:57, Paolo Barettoni <paolo.b...@gmail.com> wrote:

Of course Nikola, You are right about the monochrome images, but I suspect that Nasa will come out with some sort of false coloring, just to appeal the wide public and increase the WOW factor...

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[Glenn Newell]

Interesting thought Ian, color pallets.

All, follow up articles say the way to watch live is via NASA tv.

https://www.nasa.gov/multimedia/nasatv/#public

Article: https://www.cnet.com/science/space/how-to-watch-nasa-release-the-first-james-webb-space-telescope-images/

The press conference will be July 12th 7:30 a.m. PT.

-Glenn

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[Gary Hethcoat]

After doing a bit of research, it does appear likely that at least some of the images NASA releases will be in (false) color.  Webb has a, wait for it, FILTER WHEEL!  As some have commented, there will likely be new palettes invented for Webb.

So excited!!!

Gary

Gary Hethcoat
gary.h...@gmail.com

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[Paolo Barettoni]

Nice!

And  a little search give this "User Information" with the specs for all the filters!

https://jwst-docs.stsci.edu/jwst-mid-infrared-instrument/miri-instrumentation/miri-filters-and-dispersers

Waiting for the 12!

Paolo

[Paolo Barettoni]

Spoiler Alert!!!

This is the list of the first targets that we will see the July 12:

https://www.nasa.gov/feature/goddard/2022/nasa-shares-list-of-cosmic-targets-for-webb-telescope-s-first-images

Paolo

[Glenn Newell]

For comparison, HST filter list is here: https://www.stsci.edu/hst/instrumentation/stis/instrument-design/filters

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[Glenn Newell]

" Signaling how big a deal Webb's first images are, US President Joe Biden will release one of its first images in an event at the White House today (Monday) at 5 pm EDT. And NASA has detailed the list of cosmic objects that Webb targeted for these first observations."

[Glenn Newell]

" The preview event, during which NASA Administrator Bill Nelson will also share remarks, will stream live on NASA's website."

So 2pm Pacific

[Hitesh Dholakia]

For high res image on STSci - https://stsci-opo.org/STScI-01G7JJADTH90FR98AKKJFKSS0B.png

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[Gary Hethcoat]

OMG, what the heck is going on HERE???

Gravitational lens?

This image is ASTOUNDING!!!  I'm just sitting here with my jaw on the desk :-)  In the presentation they said that this image represents the amount of sky behind a grain of sand held at arm's length.  I'm sure at least one of you knows just how many arc seconds that is, without an assisted calculation :-)

Looking forward to someone explaining all of this!

Gary

Gary Hethcoat
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[Karen Bieber]

Hi all, 

Can someone please explain the lensing to me? I think I understand it as light bending around a gravitational force. Is that correct? Why are we seeing so much of it in this image? I don’t remember seeing it in the Hubble Deep field, but maybe I missed something.

Please help a non-scientist.

Thanks,

Karen

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[rob pfile]

that’s correct, here is a very short video from katie mack:

https://www.youtube.com/watch?v=VWjbGHb2ZC4

they specifically chose a foreground galaxy with a lot of mass to image the far-redshifted galaxies behind it being lensed. i don’t think the hubble deep field was looking for a lensing situation.

rob

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[rob pfile]

the large image they published is 4537x4630 and if i understand the spec sheet right, the near infrared imager has an FOV of 133 arcseconds square, which makes the image scale 0.0285 arcseconds per pixel. however, down on this page:

https://jwst-docs.stsci.edu/jwst-near-infrared-imager-and-slitless-spectrograph

they give the image scale as 0.065app, so maybe they drizzled this image.

or maybe i’m looking at the wrong instrument…?

rob

> On Jul 11, 2022, at 4:11 PM, Gary Hethcoat <gary.h...@gmail.com> wrote:
>
> OMG, what the heck is going on HERE???
>

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[Gary Hethcoat]

For those of you not familiar with gravitational lenses, this page is pretty good.  There is an embedded video also.

Gary

Gary Hethcoat
gary.h...@gmail.com

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[Glenn Newell]

The "grain of sand at arm's length" was also used to describe a Hubble ultra deep field image:

"the 11.5 square arc minute area is equivalent to a grain of sand held at arm's length"

https://www.conservapedia.com/Hubble_Space_Telescope

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[Rajah]

Similar FOV by hubble, https://archive.stsci.edu/missions/hlsp/relics/smacs0723-73/color_images/hlsp_relics_hst_wfc3ir_smacs0723-73_multi_v1_color.png

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[Swaroop Shere]

This comparison with Hubble capturing the same field blew my mind! https://i.redd.it/9uyhwijeo0b91.gif

Im seeing structures that did not exist in the hubble image at all! All of this with a day of exposure! 🤯

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regards,

Swaroop Shere

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regards,

Swaroop Shere

[Rajah]

Nice!

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[Gary Hethcoat]

Thank you everyone for sharing your knowledge and experience related to Hubble and JWST.  It filled in a lot of gaps in my knowledge.  Probably did similar for others.  Somehow I missed the Hubble Ultra Deep Field.  I remember seeing the first Hubble Deep Field in 1995, but missed the more interesting HUDF in 2004.  For those that want to see details on all of the Hubble Deep Fields, it is quite interesting.  I was also not aware that Hubble had an infrared camera.

Gary

Gary Hethcoat
gary.h...@gmail.com

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[Richard Thornton Senegor]

The rest of the images are here! I highly recommend people read up on each image at: https://www.nasa.gov/webbfirstimages

Mind blowing stuff! I just wish I hadn't convinced half my company to watch the livestream yesterday for an extra hour waiting around for it to start 😂

WASP-96b:

Southern Ring Nebula:

Stephan's Quintet:

Carina Nebula:

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[Carl-Erik Svensson]

Can someone explain what phenomena are happening in the optics and or sensor that produce this “chain link” pattern in the really bright stars? Also a refresher on why they burst out with those long beams of light?

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Carl

[Hy Murveit]

The long beams are definitely caused by the structure holding the secondary mirror in place, as in all RC telescopes. Some expert will have to give more detail on why. I'm going to take a wild guess and say the chain link effect is related to same, but interacting with the segmented mirrors. These affects are much dimmer than the primary (central) response to a spot of light, and much more obvious because of the bright overexposed foreground star, but I'm guessing actually exist for all stars/light in the images.

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[Richard Thornton Senegor]

I just made a post to my company Slack about the diffraction spikes the other day. We definitely have much more knowledgeable people in this group than me, so someone please come along and tell me I'm wrong :)

I also haven't found a good explanation for the "chain link" effect you're referencing, but if I had to wager a guess it's related to the light diffraction (described below) then passing through the different filters and all adding their own components to the final, composite image. So we're probably seeing the sum total of diffraction in many different spectra.

My post:

You can infer from the name that this is the result of light "diffracting" around something (i.e. the light spreads around some object). In Hubble, the telescope technology using something called "Spider Vanes" to support one of the mirrors. Incoming light diffracts around them to create the spikes.

If you're familiar with Fourier transforms, the light diffracting around the vane creates a high frequency zone in image space, which manifests as the sharp spikes. The shape of the vane and the shape of the mirror influences the shape of the spikes. In JWST's case, it has a triangular vane and hexangonal mirror. Each of those lines/points diffracts light differently. So instead of the cross you get with Hubble, you end up with 8 points for JWST: 6 from the hexagonal primary mirrors and 6 from the vanes (but 4 of the 6 overlap, so you only get 2 new ones).

Here's a neat infographic from the JWST team: https://stsci-opo.org/STScI-01G6933BG2JKATWE1MGT1TCPJ9.png

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[Glenn Newell]

I have seen a similar sized, but different aberration caused by a reflection between ASI1600 microlenses and the sensor cover glass. 

In this case it looks like little round bubbles (the shape of the microlenses).

There is a formula you can use to determine where the optical train reflections are coming from, based on their size, focal ratio, etc.

So anyway reflections between optical surfaces, vs. diffraction, is another aberration that can pop up on overexposed/"bright" stars.

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[Glenn Newell]

On such calculator:

https://astronomy.tools/calculators/dust_reflection_calculator

[Chih-hsiang Cheng]

https://youtu.be/9SyvpSe4F4k

A nice explanation at 8:32 mark. 

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