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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

#261

Post by leeoniya »

sbierwagen wrote: post #246
oAlbe wrote: 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.

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.

> So about a tenth of the width of the moon.

this is so much more digestible than "grain of sand at arm's length", and those two metrics dont feel at all equivalent -- the moon is not ten grains of sand at arm's length wide, right?

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

#262

Post by chrisweekly »

nullc wrote: post #196
april_22 wrote: post #154

Earlier quoted context omitted.

Will the JWST be able to make photos of black holes, similar to the ones the EHT made? And if yes, can the JWST be used to study black holes?

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…

> "Here is an image I took of the relativistic speed matter jet believed to originate from black hole in M87: https://nt4tn.net/astro/#M87jet ... and Webb can do a lot better than I can with a camera lens in my back yard. :)"

You, sir, have just contributed a prime example of HN comments at their best. Your astrophotography is outstanding. Thank you for sharing! :)

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

#263

Post by jcims »

oAlbe wrote: post #229
racingmars wrote: post #221

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.

Your thumb at arms length is ~2 degrees or ~120 arcminutes wide. The fingernail on your index finger at arm's length is ~1 degree or 60 arcminutes wide.

The moon is about half a degree or 30 arcminutes wide. This doesn't make sense but give it a try tonight if the moon is out.

FWIW many of the galaxies and nebula you see in astrophotography are actually bigger in the night sky than one might guess. Andromeda for example is about 6 times wider than the moon at ~3 degrees across - https://slate.com/technology/2014/01/moon-and-andromeda-rela...

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

#264

Post by systemvoltage »

crhulls wrote: post #15

Here is a Hubble side by side of the deep field for comparison https://www.facebook.com/photo.php?fbid=10159217085846758&se...

This makes the Hubble telescope even more impressive in my eyes. Built 50 years ago with presumably 60 year old tech.

> Hubble telescope was funded and built in the 1970s by the United States space agency NASA with contributions from the European Space Agency. Its intended launch was 1983, but the project was beset by technical delays, budget problems, and the 1986 Challenger disaster. Hubble was finally launched in 1990.

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

#266

Post by sbierwagen »

leeoniya wrote: post #261
sbierwagen wrote: post #246

Earlier quoted context omitted.

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.

> So about a tenth of the width of the moon. this is so much more digestible than "grain of sand at arm's length", and those two metrics dont feel at all equivalent -- the moon is not ten grains of sand at arm's length wide, right?

The moon is pretty darn small. Half a degree wide. Imagine gluing ten grains of sand together, balancing it on a fingertip, then stretching your arm out. Around a degree wide? Depending on your grain of sand, of course.

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

#267

Post by pkaye »

lbrito wrote: post #102

I remember reading something in the lines of: we know this nebula to be composed of gasses X and Y, which have colors A and B. As a layman it was unclear to me if this statement means they are applying a color palette to a monochrome image(s) using some educated guesses or something else. Is infrared the only (or the most convenient, most useful etc) spectrum visible given the great distance? If we could get close en…

They have dozens filters on the telescope so they take multiple pictures at different wavelength and assign colors to them and combine them.

The galaxies from the early universe would not be visible in the visible spectrum since due to red shift, its become infrared spectrum. Also infrared spectrum can see through stellar dust so some things become more transparent in the photos.

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

#268

Post by jcims »

racingmars wrote: post #221
jcims wrote: post #205

Earlier quoted context omitted.

I really wish astronomers would come up (or use) a standard mechanism for indicating the field of view of an image. The scale of this one in the night sky is much larger than the deep field one.

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...

I know that's usually there. I'd just love to see a little map scale bar or something in EXIF.

[-----------] °

[--------] '

[----------------------] "

[----------------] ,,"

Super easy.

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

#270

Post by jonplackett »

deelowe wrote: post #109
capableweb wrote: post #45

Earlier quoted context omitted.

Yeah, that's not very good implementation. PetaPixel usually have good content, but using a GIF to compare these two images? Come on! You can see the compression artifacts very easily.

This was also recently posted on reddit: https://johnedchristensen.github.io/WebbCompare/

Was J J Abrahams involved in Webb, because it really seems to produce nice lens flair
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