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How clear will the James Webb Space Telescope images be compared to other telescopes?

I mean mainly for things like:

Pluto

Ceres

Left above: Pluto by Hubble Space Telescope. Right: Ceres by Hubble Space Telescope. Below: exoplanet HIP 65426 b (bottom-left) by Very Large Telescope. Click the image for full size.

Exoplanet HIP 65426 b (bottom-left)

Peter Mortensen
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Joe Jobs
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  • The primary purpose of the Webb is not improved resolution (but it will have slightly resolution than Hubble). The primary purpose is improved light gathering capabilities in frequencies that are blocked by the atmosphere. The hope is that the Webb will give some insight into the "dark ages", the period between when the universe became transparent and when stars first started forming. – David Hammen Jan 01 '22 at 14:15

1 Answers1

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The angular resolution of Webb will be about the same as Hubble. Although Webb has a significantly larger main mirror, it is optimized for infrared. The longer wavelengths mean that it is diffraction-limited to somewhat better 0.1 arcseconds (a small coin at 40 km).

At the wavelengths that Hubble and Webb can both observe at (the near infrared), Webb beats Hubble. But Hubble can also observe at near-ultraviolet wavelengths, and at those wavelengths, Hubble beats Webb.

As infrared is absorbed less by interstellar dust, and it can collect more light and see objects that are 100 times fainter than those that Hubble can see, its images will be "detailed and spectacular" (source).

Peter Mortensen
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James K
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  • The Hubble beats the Webb at ultraviolet wavelengths because the Webb doesn't have any UV sensors. – David Hammen Jan 01 '22 at 13:41
  • That's not what I meant. The resolution achieved by Hubble at UV wavelengths betters the resolution achieved by Webb at any wavelength. So if comparing this, then Hubble has higher resolution. But that (it can be argued) is not comparing like with like. At wavelengths that both can sense, Webb has higher resolution. – James K Jan 01 '22 at 13:43
  • Which existing New Horizons photo of Pluto or Dawn photo of Ceres are most close to the photos JWST can take of those dwarf planets? I mean in terms of resolution, color doesn't matter – Joe Jobs Jan 02 '22 at 14:33
  • "The angular resolution of Webb will be about the same as Hubble." The resolution of the dwarf planets by New Horizons and Dawn is many times greater than the resolution achievable with Webb or with Hubble. Pluto is about 0.1 arcsecond across, so it will be about 1 pixel with either Webb or Hubble (though post processing tricks may be able to bring out more details) – James K Jan 02 '22 at 15:39
  • The resolution of the dwarf planets by New Horizons and Dawn depends on how far they were at the moment of taking the photos. I guess JWST can take better pictures of Ceres than Dawn when it left the Earth – Joe Jobs Jan 03 '22 at 07:36