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James Webb first images – complete set of high resolution shots now live

webbtelescope.org

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Re: James Webb first images – complete set of high resolution shots now live

#241

This kind of stuff is really awe-inspiring. I have a couple of questions for anyone who is knowledgeable on the subject: 1. Looking at the light from the tiny red-shifted galaxies that are ~13 billion years old... would the Milky Way appear the same to an observer ~13 billion ly from us? 2. What is the cause of the star pointed artifacts (specifically, having 6 major "points") for particularly bright objects? If you…

The points are caused by the support arms of the secondary mirror.

Re: James Webb first images – complete set of high resolution shots now live

#242
post #229

Earlier quoted context omitted.

Is there a way to rapport an arcmin to a measurement that would be more easily understandable? Not necessarily as a multiple of grains of rice.

7.3 arcminutes = 16 light-years

That's the distance of an object away that has a parallax of 7.3 arcminutes and a baseline of 1AU. The 7.3 arcminutes referenced here is the width of the image on the celestial sphere.

Re: James Webb first images – complete set of high resolution shots now live

#243

This kind of stuff is really awe-inspiring. I have a couple of questions for anyone who is knowledgeable on the subject: 1. Looking at the light from the tiny red-shifted galaxies that are ~13 billion years old... would the Milky Way appear the same to an observer ~13 billion ly from us? 2. What is the cause of the star pointed artifacts (specifically, having 6 major "points") for particularly bright objects? If you…

1. Yes pretty much.

2. Yes the artifact shape is related to the mirror shape, and the support arms which block some light. this is called a Diffraction spike. There are a bunch of fake web telescope image videos on YouTube with 4pointed diffraction spikes so you can tell they are taken from a different telescope.

https://en.wikipedia.org/wiki/Diffraction_spike

Re: James Webb first images – complete set of high resolution shots now live

#244
post #229

Earlier quoted context omitted.

The image details do have the dimensions listed in a standard measure down under the "Fast Facts" section; I assume this will be included for every image release. The deep field image says it's about 2.4 arcmin across[1], Stephan's Quintet image is about 7.4 arcmin across[2], etc. [1] https://webbtelescope.org/contents/media/images/2022/035/01G... [2] https://webbtelescope.org/contents/media/images/2022/034/01G...

Is there a way to rapport an arcmin to a measurement that would be more easily understandable? Not necessarily as a multiple of grains of rice.

I always translate it in my mind to full moons. 30 arcmin == diameter of full moon as seen from earth.

Re: James Webb first images – complete set of high resolution shots now live

#245

This kind of stuff is really awe-inspiring. I have a couple of questions for anyone who is knowledgeable on the subject: 1. Looking at the light from the tiny red-shifted galaxies that are ~13 billion years old... would the Milky Way appear the same to an observer ~13 billion ly from us? 2. What is the cause of the star pointed artifacts (specifically, having 6 major "points") for particularly bright objects? If you…

on 1., I'm not sure but I'd guess so, yes.

on 2., you are seeing Diffraction Spikes[0] which are artefacts of the telescope's design.

[0]: https://en.wikipedia.org/wiki/Diffraction_spike

Re: James Webb first images – complete set of high resolution shots now live

#246
post #229

Earlier quoted context omitted.

The image details do have the dimensions listed in a standard measure down under the "Fast Facts" section; I assume this will be included for every image release. The deep field image says it's about 2.4 arcmin across[1], Stephan's Quintet image is about 7.4 arcmin across[2], etc. [1] https://webbtelescope.org/contents/media/images/2022/035/01G... [2] https://webbtelescope.org/contents/media/images/2022/034/01G...

Is there a way to rapport an arcmin to a measurement that would be more easily understandable? Not necessarily as a multiple of grains of rice.

A minute of arc is one sixtieth of a degree. (A "minute", get it?)

The moon is between 29.4 and 33.5 arcminutes wide, depending on where it is in its orbit. So about a tenth of the width of the moon.

Re: James Webb first images – complete set of high resolution shots now live

#247
post #234
post #64

Direct links -- Stephan's Quintet (NIRCam and MIRI Composite Image): https://stsci-opo.org/STScI-01G7DB1FHPMJCCY59CQGZC1YJQ.png Southern Ring Nebula (NIRCam and MIRI Images Side by Side): https://stsci-opo.org/STScI-01G79R28V7S4AXDN8NG5QCPGE3.png “Cosmic Cliffs” in the Carina Nebula (NIRCam Image): https://stsci-opo.org/STScI-01G7ETPF7DVBJAC42JR5N6EQRH.png Webb's First Deep Field (NIRCam Image): https://stsci-opo.org…

> “Cosmic Cliffs” in the Carina Nebula (NIRCam Image): > https://stsci-opo.org/STScI-01G7ETPF7DVBJAC42JR5N6EQRH.png Is this for real?! It looks like it came right out of a Sci-Fi movie/book. Could anyone explain how much of this is post-editing magic?

It’s real light, just color shifted as the JWST is designed to look at severely very distant and thus red shifted objects. The nebula is however much closer than that.

Anyway, that looks like science fiction because science fiction borrowed that look from astronomy. https://en.wikipedia.org/wiki/Nebula

Re: James Webb first images – complete set of high resolution shots now live

#249
post #196

Earlier quoted context omitted.

Producing an "image" of a black holes requires astronomical, ahem, resolution because they're so far away (thankfully). To achieve this kind of resolution you need an aperture of thousand of kilometers. The EHT images are created using synthetic aperture techniques to create an effective aperture with a diameter of earth's orbit around the sun. But this is only currently possible at radio frequencies due to our abili…

Thank you! Another question: are they already planning a successor to JWST? Is something better even possible? If it took more than 30 years, we should start sooner than later :)

https://en.wikipedia.org/wiki/List_of_proposed_space_observa...

https://en.wikipedia.org/wiki/SAFIR is the closest to a proposed JWST successor; the others largely serve different purposes.

Re: James Webb first images – complete set of high resolution shots now live

#250

Earlier quoted context omitted.

No, there's none of that. These pictures aren't being used for any kind of science. They're 100% PR pieces, made to look pretty - which is fine!

Which makes me wonder how all these galaxies and nebulas would look like in real life. Would they look similar to how they colored it? Are those images maybe potraying a completely wrong reality?

If you were to fly into these nebula in some kind of spaceship they wouldn't be any brighter than they appear in the night sky from Earth. They would just look way way bigger. The frustrating thing is that our eyes start to respond differently to colours when the light is really really faint. So we would probably perceive them as a grayish green haze. If the image was brightened artificiallythen we would see it as mostly red, with some browns and blues.
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