Amazing new images from Hubble Space Telescope (HST) of Uranus and Neptune! https://earthsky.org/space/hubble-space-telescope-sees-storms-uranus-neptune
Here are the Hubble site images: http://hubblesite.org/images/news/release/2019-06
Uranus especially continues to surprise - Voyager IIs flyby timing and its camera's filterset certainly misled people about how dynamic its atmosphere can be.
In the continuing absence of the followup probes the two ice giants so badly deserve, I look forward to what the ELTs and next gen adaptive optics will achieve.
GMT arrival = 6 years with any luck.
P
Actually, considering the large portion of the visible globe of Uranus covered by that seemingly bright cloud (I presume this is a near IR image), has it had any
effect on the planet's magnitude in the visible?
Excellent questions Antipode and Dolphin and further inquiry into details regarding Uranus’s north polar cloud and Neptune’s new dark spot have been ongoing. Two abstracts gleaned from Hubble’s OPAL (Outer Planet Atmospheres Legacy) website https://archive.stsci.edu/prepds/opal/ are interesting in this regard. For the north polar hood of Uranus https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL077654 and for Neptune http://adsabs.harvard.edu/abs/2018AJ....155..117W .
Here are pictures I personally took with a 235mm Schmidt–Cassegrain and the aforementioned filters on October 18, 2018. The contrast is evident in the IR image, discernible but subtle in R, and completely absent in the G+B (it is absent in both of those, of course, for it to be absent in the sum of them).
At right is a composite where I used the luminance of the IR image, then colored it with the RGB image but with the red plane doubled. It's a nice appearance, but a bit past the bounds of "true color." The fact that both the hue and the brightness of the cap are different from the rest of the planet speaks to the fact that both IR and R show the hood.
There is also a thin equatorial belt that other observers captured but I did not.
But green does not. So we should expect the Voyager camera, were it taking an image of Uranus today, to turn up something blank because of the lack of a proper red filter.
From the OPAL site the images of Uranus are taken with the WF3-UVIS filter camera on Hubble and are not IR images. There are 63 UVIS(ultra violet-visual) filters http://www.stsci.edu/hst/wfc3/ins_performance/ground/components/filters. My guess is that the images published were from the F845 filter which shows the N polar cap AND the compact methane ice cloud at the polar cap edge https://solarsystem.nasa.gov/news/839/hubble-reveals-dynamic-atmospheres-of-uranus-neptune/
As the compact cloud is considered an upper atmospheric phenomenon (sometimes visible in amateur telescopes) and the large polar cap is not a high troposphere or stratospheric phenomenon, that a visible light view of Uranus might still appear relatively bland! With the north polar cap of Uranus facing the sun however one wonders whether it might become visible as the planet’s summer progresses.
The F845 filter is certainly what I'd call infrared, whatever bin they happened to organize it into. There may be no exact sharp cutoff of the longest wavelength a human eye can see, but I don't think anyone considers >800nm to be red as opposed to IR.
No, I see absolutely no features in Uranus with the naked eye, and I'm not sure that anybody ever has with any telescope. There are certainly bright white storms that appear at times, but they push the limits of resolution. While the gradient in red can in principle be seen with the human eye, it is drowned out by overwhelmingly higher levels of brightness in blue and green. When I add the red plane to the blue and green in Photoshop, I can hardly even notice its presence (which is why I doubled it to make that image above).
I think at the limits of terrestrial telescope, Uranus is a blank disc, and I've seen it many times. It's a very appealing color, but that's all one sees. From a vantage point inside the Uranus system, the enormous increase of resolution might make the slight contrast in color emerge.
Here is a conventional RGB color image that I took in 2016. This is basically what it looks like to my eye.
Appreciate your expert commentary JRehling! While visible spectrum images of Uranus may remain bland we are fortunate to have the capabilities of Hubble and large ground based telescopes (Keck, Gemini at present) to image Uranus in the near IR and methane/hydrogen filter views. It is humbling (for myself at least) to review the literature of the last 20 years and discover papers, such as https://www.sciencedirect.com/science/article/pii/S0019103518300320?via%3Dihub of Sromovsky et al providing images spanning almost a quarter of Uranus’s 84 year sol revolution (see first figure below) revealing changes in the atmosphere we might not otherwise be aware of. (as in Fig. 3 below from that paper).
A new publication in Geophysical Research Letters concerning Neptune's new Great Dark Spot can be found here: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2019GL081961
The December 2019 issue of Sky and Telescope has an nice review article by Ken Croswell: "Uranus and Neptune The Neglected Ice Giants".
Funnily enough, I remember an article of his in an issue of Astronomy Now, back in 1989, called: "Neglected Nereid".
^^ Did this article have a Concept mission for Uranus/Neptune ?
An article speculating on the JWST observations concerning Uranus and Neptune. https://www.nasa.gov/feature/goddard/2020/examining-ice-giants-with-nasa-s-webb-telescope
A summary presentation concerning the 2014-2019 Hubble OPAL observations concerning Uranus and Neptune may be found here. https://core.ac.uk/download/pdf/288485751.pdf
Polar haze brightening and small storms continue on Uranus and observations of the occurrence and evolution of dark vortices on Neptune are highlighted. A six year orbital mission of Neptune is suggested for up close observations of a dark vortex.
The authors propose continued Hubble observations of Uranus and Neptune in 2020. https://ui.adsabs.harvard.edu/abs/2020hst..prop16266S/abstract
Ooh, nice!
Thanks for that.
P
ps Bring on the ELTs and advanced AO!
An article in Physics World published on Dec. 8th https://physicsworld.com/a/things-we-dont-know-about-uranus-and-neptune/ summarizes a presentation by Dr. Heidi Hammel at the RAL Space 16th Appleton Space conference https://www.ralspace.stfc.ac.uk/Pages/16th-Appleton-Space-Conference.aspx , concerning past, present and future studies of the Ice Giants and their moons.
Wow, a Hubble-Neptune Dark Spot update! A Dark Spot discovered in 2018 has reversed a latitudinal migration and possibly fragmented. The report appears here: https://www.nasa.gov/feature/goddard/2020/dark-storm-on-neptune-reverses-direction-possibly-shedding-a-fragment. The article mentions "Hubble snapped many of the images of the dark spots as part of the Outer Planet Atmospheres Legacy (OPAL) program, a long-term Hubble project, led by Amy Simon of NASA's Goddard Space Flight Center in Greenbelt, Maryland, that annually captures global maps of our solar system's outer planets when they are closest to Earth in their orbits."
Some lite reading in the NY times on the recent Neptune dark spot! https://www.nytimes.com/2020/12/22/science/neptune-dark-spot.html
Some updated information on the OPAL web site here: https://archive.stsci.edu/prepds/opal/
Seems I cannot contribute a significant post from the NASA OUTER PLANETS ASSESSMENT GROUP (OPAG) in the already existing UMSF topic and so I post it here, https://www.lpi.usra.edu/opag/meetings/aug2021/OPAG2021-Aug-Agenda.pdf as part of the meeting’s agenda pertains to HST imaging of Uranus and Neptune. My apologies if this appears elsewhere.
Wow! Hadn't seen this Hubble video of Neptune before. https://hubblesite.org/contents/media/videos/2020/59/1299-Video
nice!
only if hubble looked at neptune for longer, we could have seen how the 2 spots get along without smashing
A NASA post from yesterday https://www.nasa.gov/feature/goddard/2021/hubbles-grand-tour-of-the-outer-solar-system, provides some beautiful images, a nice video and interesting commentary concerning HST's most recent OPAL survey of the outer planets. See also the Hubble site post here: https://hubblesite.org/contents/news-releases/2021/news-2021-047
Jupiter 2021 maps: https://archive.stsci.edu/missions/hlsp/opal/cycle28/jupiter/
Saturn 2021 maps: https://archive.stsci.edu/missions/hlsp/opal/cycle28/saturn/
Uranus 2021 maps: https://archive.stsci.edu/missions/hlsp/opal/cycle28/uranus/
Neptune 2021maps: https://archive.stsci.edu/missions/hlsp/opal/cycle28/neptune/
you can also find the same maps here
https://archive.stsci.edu/prepds/opal/
For myself, the appearance of Uranus is most amazing! The description of the HST imaging details of this planet https://hubblesite.org/contents/media/images/2021/047/01FM0NV7Y1WBDXM0SS4R7NJ1X4?Tag=Uranus&news=true combined with this link to the filters WFC3 uses to make composite images https://hst-docs.stsci.edu/wfc3ihb/appendix-a-wfc3-filter-throughputs solidifies the comments made by JRehling about the appearance of Uranus earlier in this topic.
Yes, that polar hood is absolutely enormous, and the entire planet is probably a bit brighter as a result. Pure bad luck that Voyager 2 didn't see it, if this phenomenon occurs at either hemisphere's equinox.
Some encouraging news https://www.nasa.gov/feature/goddard/2021/hubble-instruments-remain-in-safe-mode-nasa-team-investigating for HST continuing to provide us with periodic views of Uranus and Neptune.
A new article, published 4/11/’22, concerns Neptune’s atmospheric temperature variation over the last 20 years. Although data from Hubble was not used, infrared observations from Spitzer and multiple, large ground-based telescopes (8-10 meter class instruments) provided more than 95 images acquired between 2003 and 2020 at wavelengths ranging from 7.7 to 25.5 μm. The full article is here: https://iopscience.iop.org/article/10.3847/PSJ/ac5aa4
A new article concerning the latest views from Hubble on Jupiter and Uranus was published yesterday and is here: https://www.nasa.gov/feature/goddard/2023/hubble-monitors-changing-weather-and-seasons-at-jupiter-and-uranus
New Webb image of Uranus:
https://webbtelescope.org/contents/news-releases/2023/news-2023-117.html
I played with the image a bit to pull out a bit of extra detail (in the bright region particularly). Anyone with better skills than mine especially in sharpening the image might be able to see more.
Phil
Nice improvements on an already nice image!
I like how the rings had only been detected previously by one ground-based telescope, and the JWST, to say the least, detects them in amazing detail.
As with JWST's previous release of a Neptune image, the trick here is using IR wavelengths that greatly darken this particular planet, allowing longer exposures that pump up the rings without losing them in the glare. A storm on the left seems to have clouds that rise far enough above most of the methane in the atmosphere that it glares rather prominently.
Beautiful!
The axial tilt really highlights how well Voyager 2 performed during its encounter (and with an iffy scan platform too) - all the most important observations and measurements (moons, rings, atmosphere, fields/particles, occultations etc) packed into the six hours or so either side of closest approach.
Topic title updated to reflect JWST's new contributions.
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