Show HN: A JWST/Hubble deepfield comparison on a zoomable/pannable map interface

https://academo.org/demos/james-webb-vs-hubble-telescope-comparison/

by outputchannel • 4 years ago

61 36 4 years ago

academo.org

dirslashls• 4 years ago

Nice. It would be good to have a way to reset to get back to the initial state after zooming/panning.

aardvarkr• 4 years ago

This is incredible. Thanks for sharing it!

revskill• 4 years ago

These are annoying to me because lacks of real difference from a senior astronaut viewpoint. As a normal user, the only difference i could see is just "brighter", anything more to add to the details ?

Else i could say, just the same.

atoav• 4 years ago

JWST shows a much bigger part of the wavelength spectrum. That means it can image things that would just not show up in Hubble.

E.g. think about far away galaxies that have been redshifted so much (due to the expanding universe) that they fell below the lower wavelength threshold of Hubble.

Synaesthesia4• 4 years ago

Yes, also cooler objects show up, which are otherwise invisible and you can see through interstellar dust and clouds better.

testcase_delta• 4 years ago

Zoom in on a small section of sky and toggle between James and Hubble. James reveals many additional galaxy in each tiny slice of image. Probably hundreds or more in that one image alone.

falseprofit3• 4 years ago

Check out some of the reddest galaxies in the Webb image. Even the big ones are entirely invisible on the Hubble image.

Azrael30003• 4 years ago

Check out the video by Scott Manley, he explains quite a bit: https://www.youtube.com/watch?v=0FWO1Pvbhq4

arriu• 4 years ago

I love that there is a star showing some drift

Azrael30003• 4 years ago

There's no drifting there. What you are seeing is gravitational lensing. The light of (most likely a galaxy) is bent around another galaxy or star which distorts its appearance. Also this means it can potentially show up multiple times on the image (e.g. opposite side w.r.t. the lensing object)

outputchannel2• 4 years ago

Thanks for the comments! It does look like some stars may be exhibiting stellar drift, I've isolated an example here: https://academo.org/demos/james-webb-vs-hubble-telescope-com... This is from the middle-right side of the deep field. If you look slightly below the two central galaxies, there is what looks to be a foreground star (I say that due to its brightness and the fact it has a starburst effect) and between the two frames, there seems to be a noticeable shift in position that doesn't occur with other objects.

nabla9• 4 years ago

JWST and Hubble have roughly similar angular resolution. Hubble marginally better. JWST needs larger mirror for the same angular resolution because it uses longer wavelengths.

  Hubble: 0.04  arcsec at 500 nm 
  JWST:   0.068 arcsec at 2 μm

The difference is in wavelengths, image quality, and light collecting ability (size of the mirror). Hubble has to stare longer into a same spot to collect the same amount of light as JWST.

(If I remember correctly JWST took this image in less than 12 hours, Hubble stared at it for much longer. Correct me if I'm wrong).

sph• 4 years ago

Would JWST have made a more detailed picture if it had stared on that spot as long as Hubble did?

Synaesthesia4• 4 years ago

The longer you "expose" the more detail is revealed yes.

gliptic2• 4 years ago

Resolution would not improve, but contrast would and you would be able to see fainter objects with less noise.

0x_rs• 4 years ago

Hubble's composite of SMACS took 5 orbits, which ends up being about a couple hours maximum. Most websites talked about the deep fields such as XDF (hundreds of orbits) while showing the comparison between the RELICS and JWST pictures, which I believe was very misleading from how this is repeated. Not to detract from its capabilities, of course.

fvold• 4 years ago

I want to see a comparison of the infrared from Hubble vs the infrared from James.

I also want to normalize calling JWST just "James" :)

Synaesthesia4• 4 years ago

The Hubble only went into very near infrared, nothing like JWST. Also JWST is a million miles from earth so it is ultra cold.

I like "James Webb Science Telescope" for JWST.

falseprofit3• 4 years ago

Just Wonderful Space Telescope

Synaesthesia4• 4 years ago

This isn't a real image of an exoplanet right? The one in the background. Nowhere does it say that, which I think is beyond the ability of even JWST, to resolve an exoplanet at 50 light years?

https://www.nasa.gov/image-feature/goddard/2022/nasa-s-webb-...

hrnnnnnn2• 4 years ago

The image in the background is an artist's rendition. The graph is the real image.

Exoplanets are too far away and too small to image directly.

Cthulhu_2• 4 years ago

I do hope they can train the JWST at a close-by star and at least see a dot that represents an exoplanet.

privong2• 4 years ago

Exoplanets are too far away and too small to image directly.

If you mean resolving details of the exoplanet, then yes that is currently true. But we have imaged exoplanets directly, meaning taken an image of a star where one can also see the planet directly in the image. [0] has a list of directly imaged exoplanets.

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

holoduke• 4 years ago

Would there be a moment we cannot zoom in further because we hit the event horizon with the jwst? Or are there still hidden galaxies behind what we can see with the jwst?

Cthulhu_2• 4 years ago

I think it won't be a hard border per se, but it'll just turn into extremely redshifted noise at some point; beyond infrared you end up in microwaves, which leads to the cosmic microwave background radiation: https://en.wikipedia.org/wiki/Cosmic_microwave_background

falseprofit3• 4 years ago

The furthest back potentially visible stuff before the dark age won’t be galaxies, which formed after the first stars. We still have never seen a first generation star, and I’d be surprised if Webb could.

RcouF1uZ4gsC• 4 years ago

As an aside, does anyone on HN know why one telescope’s name includes a first name and the other doesn’t.

We don’t call the first telescope the Edwin Hubble Space Telescope

q1w22• 4 years ago

Webb is a much more common surname than Hubble.

gumby• 4 years ago

I think it's because they are two syllables. After a short time objects named after people* (Carnegie Mellon, FDR Drive etc) tend to lose the association with the person so honored and just become strings. This is doubly so for names of international scope.

Think of Google, Facebook, Netflix, Workday, Coinbase: two syllables, each name an iamb (which is especially effective in English). Sure, there are numerous counterexamples (microsoft, Amazon), but generally the corners get knocked off and even turn into acronyms in public usage (GM, GE).

Single syllables are too short for infrequently used words (this appears to be true for any language) -- you don't want to waste a lot of time saying "am" since you say it a lot; when you say "biceps" you want enough variability that your brain has time to parse it.

Show HN: A JWST/Hubble deepfield comparison on a zoomable/pannable map interface

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