James Webb Space Telescope, information, updates and discussion Options

[Redstone]

The manufacture of the JWST mirror blanks has now been completed.

Despite this milestone, the fate of JWST is still somewhat precarious, because although the scientific bang from the telescope is expected to be huge, the bucks required have increased to a staggering $4.5 billion. A Space.com article on the squeeze in NASA's space-based astronomy plans gives some background.

The JWST home page can be found here.

The Space Telescope Science Institute, which runs Hubble, also has a site here. As does ESA.

[scalbers]

Webb in the main IR wavelengths should match Hubble resolution in visible light. I'm unsure if Webb could/will show higher resolution if they took images just concentrating on its shortest wavelengths around 0.6 microns. The diffraction effect is less at 0.6 microns and the wavefront errors appear low enough to support higher resolving power. The F070W NIRCam filter might do the trick around 0.7 microns:

https://jwst-docs.stsci.edu/jwst-near-infra.../nircam-filters

With the dwarf planets I suppose Webb might be able to help learn to things spectroscopically using MIRI.

[StargazeInWonder]

In general, the IR spectroscopic capabilities of Webb are unmatched, and will provide a superior capacity to that of missions that have actually visited those worlds. JWST will provide IR spectroscopy of Mars better than that of any spacecraft that has ever orbited Mars. Better of Saturn than Cassini. Etc. Of course the spatial resolution of JWST will not match the spatial resolution of MRO at Mars or Cassini at Saturn, but will still resolve and differentiate large features quite well.

For any specific target, it's another matter whether or not IR spectroscopy answers the question we would like to answer. Sometimes the composition of aerosols and surface units is addressed with spectroscopy and sometimes not. We really won't know before the observations are made. Surely it will answer some questions and leave some unanswered.

As scalbers noted, the spatial resolution of JWST is comparable to HST's visible-light resolution. The highest spatial resolution achievable with HST is in UV, which provides better diffraction limits than visible light. JWST won't beat that resolution. And ground-based observations, which already better spatial resolution than HST and JWST, will be even more impressive when the larger telescopes being constructed now begin operation in the next decade.

It seems safe to say that, when possible, taking the highest possible spatial resolution image of a target concurrent with the great spectral resolution of JWST will allow better science than either would produce alone.

[rboerner]

In general, the IR spectroscopic capabilities of Webb are unmatched, and will provide a superior capacity to that of missions that have actually visited those worlds. JWST will provide IR spectroscopy of Mars better than that of any spacecraft that has ever orbited Mars. Better of Saturn than Cassini. Etc. Of course the spatial resolution of JWST will not match the spatial resolution of MRO at Mars or Cassini at Saturn, but will still resolve and differentiate large features quite well.

For any specific target, it's another matter whether or not IR spectroscopy answers the question we would like to answer. Sometimes the composition of aerosols and surface units is addressed with spectroscopy and sometimes not. We really won't know before the observations are made. Surely it will answer some questions and leave some unanswered.

Any specific expectations about the ice giants and their satellite systems? NASA published a teaser story in 2020 that promised that "soon after its launch", Webb would "unlock the secrets of the atmospheres" of the ice giants, but did not go into much detail, or said anything about the satellites.

https://www.nasa.gov/feature/goddard/2020/e...-webb-telescope

[StargazeInWonder]

Uranus, Neptune, and the uranian satellites will indeed be studied by JWST soon/already. I don't notice Triton being mentioned, but maybe it's hidden in another proposal, or maybe it didn't make the cut for Cycle 1; it's certainly a worthy target that wouldn't be ignored indefinitely.

https://www.stsci.edu/jwst/science-executio...rams/cycle-1-go

https://www.stsci.edu/jwst/science-executio...on.html?id=1585
https://www.stsci.edu/jwst/science-executio...on.html?id=1598
https://www.stsci.edu/jwst/phase2-public/1786.pdf

I would expect some outstanding science to result. To some extent, we won't know what spectroscopy in JWST's wavelengths is capable of until we get the first results, but the potential is excellent.