I finished my first good image of Uranus.
Planet is colorized from three filtered images (orange, green, blue).
Slightly brownish color of rings is entirely artificial.
That's pretty neat, ^.^, though the rings look a bit bright =o.
Yes, rings look bright, because their brightness is enhanced.
Rings are in fact barely visible.
Original exposition times were 15.36 s for rings images (clear filter) and 0.72 (blue filter), 1.44 (green filter), 5.76 (orange filter) for Uranus images.
Despite of these exp. times, rings were still very dark (much darker than Uranus).
Probably highest resolution image of Uranus with some details (~12 km/pix).
Color from green, violet and synthetised images.
Hey thats very nice! Has this dataset been ignored because it was assumed nothing much could be squeezed out of it?
P
Possibly. But I think, that lots of information is still hidden in these images. And for long time, these are best images of Uranus.
Great work! I have always focused on the moons, never the planet.
Ever since the original data was released, it always seemed to me that the response was 'big bland boring ball......oooh look at that pretty Miranda over there!' Now that the planet has gone through equinox and we have Hubble and Keck etc, we know better, but still the popular assumption is that the planet is just a big featureless fuzzy ball.
Given that you are right, and that we are likely to see Neptune close up (Argo?) before we see Uranus close up, I for one am very interested in what you find in this dataset. Maybe with a bit of suitable processing it will surprise us all!
P
If you haven't seen it, you should check out http://www.planetary.org/blog/article/00002289/, posted with lots of his comments about processing. The key thing of interest in reply to antipode's post is that he found no features in the images that were significant enough to make it worthwhile to rotate the three frames in 3D space to align them before creating the color composite.
Also, regardless of whether Argo is selected, I think Neptune will be visited again before Uranus, because of Triton.
I have seen Bjorn Jonnsson's image of Uranus and in fact, I use this image as color ethalon
Uranus or Neptune? Don't forget on Uranus Orbiter! Team from JPL (also APL?) has mission scenario within New Frontiers budget. They planning solar! powered orbiter.
It's actually quite interesting to attempt to squeeze out some details from these images but having worked mainly on Cassini images recently the image quality really sucks. Here is a quick and dirty version of image C2682833.IMQ:
I was wrong! Is one image with slightly higher resolution, but photographed by Voyager 2 before image, which I posted above. But in this image is surface actually closer, so resolution is 11.5 km/pix compared to 11.7 km/pix in picture above.
And something to Uranus orbiter:
http://www.lpi.usra.edu/decadal/opag/UranusOrbiter_v7.pdf
http://www.lpi.usra.edu/decadal/opag/UranusOrbiter_v7_Authors.pdf
http://spacepolicyonline.com/pages/images/stories/PSDS%20Sat1%20Hofstadter-Uranus%20and%20Sat%20Sci.pdf
Online presentation (with audio) is somewhere too, but I don't know where.
Best image of Uranus south pole. Circular feature is real (some details not). Nearly horizontal lines are artifacts from flatfielding.
The slightly lighter core inside the darker second ring could be faceted like the Saturn hexagon. But any sort of blips at single 60-degree intervals from each other is enough to make part of a blurry circle look like part of a hexagon.
Pretty cool to see structure there, though.
Effectively highest resolution view from any of Voyagers. Two shots after well known Miranda mosaic images. NAC frames over one WAC frame. Color is artificial, but very close to real. It's based on the HST photometry. Resolution is 280 m/pix.
Wow! Love your work.
Thanks Decepticon!
And new image from Uranus system - moon Ariel. Resolution of this stereopair is around 1.55 km/pix.
Moon Ariel resampled at 1 km/pix (real resolution ~ 1.2 km/pix).
Stunning!
Nice work, keep it coming!
WOW! That's the best look at that moon I've ever seen!
Actually its so good I'm looking at that dramatic resurfacing in a new light. There's a real paucity of medium to large craters in that image?
P
Stefan and Ugordan: Thanks!
Antipode:
Actually yes, surface of Ariel is relatively young. I don't know about any large crater on that moon. Even medium craters are scarce.
Moreover some parts looks like surface of Enceladus. In terms of geologic activity, Ariel is perhaps between Enceladus and Dione.
Great work! That is the mosaic I based my first LPSC conference on http://www.planetary.org/blog/article/00001362/
Three images of Titania. All resampled from original resolution 6.7 km/pix, 4.6 km/pix and 3.4 km/pix.
Very nice work.
Ditto.
Im enjoying this thread, and enjoying the better press Uranus is finally getting lately (jokes aside, I think the active equinox atmosphere has helped silence the 'totally bland' press the planet has had since 1986).
Back to the moons. I wonder (Wunda? ) how many decades it will be before we get a better peek at Umbriel's strange Wunda? Looks very Iapetaen.
P
Ted: Thanks!
Antipode:
I'm always enjoying work with Uranus moons, I hope this is another small piece of work which leads to support new mission to these strange lands.
"Wunda? Looks very Iapetaen" I think so too .
Ugordan:
All three images shares same color data from medium resolution image.
I used different processing technique to highest resolution image which leads to slightly bigger color differences.
So I think color shift is real, but slightly more enhanced than on another two images (and terminator regio isn't so good visible on these two images).
I have also noticed the color shift.
It looks like a calibration artifact at first, but then if you look closer it looks like an albedo feature as it extends clockwise all the way to the sunlit limb at 5 o'clock. I think that's the most color variation I've seen on Uranus' moons.
You see? THIS is why I love UMSF so much... You Image Mages delve into the misty archives, drop the old, forgotten images dumped there into your cauldrons, give a good stir and whumpf! out come amazing new views of these distant worlds...
Many thanks for sharing these beautiful pics, guys.
Ugordan, Tedstryk:
In case of color shift near the terminator, I think that's combination of imperfections of calibration (which are more evident at low brightness level) and real surface color. I looked at maps and redder hemisphere is around 90° longitude. I think it's the leading hemisphere.
Stu:
Image Mage, nice phrase
"forgotten images dumped there into your cauldrons"
My secret ingredient is bat's ear but keep it under your hat
Last in set - Oberon.
Resampled at 3 km/pix. Real resolution 7 km/pix.
Here's a color version of Titania using calibrated data from the http://pds-rings.seti.org/voyager/iss/calib_images.html:
Machi´s version of the Oberon data set can be used to add a tiny bit of coverage along the terminator of Steve Albers´ map. I assume the color processing is different and just roughly adjusted the brightness.
While I´m at it, here´s a quick reprojection of the Titania nightside coverage dicovered by Ted Stryk onto Steve´s map (looks slightly mismatched, but dayside features line up in this position).
Anaglyph of Titania. It's based on synthetic frame between last two high resolution Voyager images of Titania.
Edges were removed.
Cross-eye stereo image of Titania. Synthetic image is more precise than that one in previous anaglyph.
Resampled to ~2 km/pix. Edges were cropped from synthetic image.
Daniel, you're a wizard. These are AMAZING.
Agreed, this is amazing. Interestingly the anaglyph reveals that the surface is a bit depressed farther away from the big fracture than can be easily seen in the original imagery.
I want a Uranus orbiter! ;-)
I noticed that the (bear with me on the terminology here because this is Uranus & everything's tilted 98 deg) 'north polar' area seems depressed as well 'above' the large crater in the crosseyed pair.
Interesting little world among many there, well worth further investigation. Sure hope I live that long.
Thanks!
I see many topographic details, but one must be careful about interpretation. For example some "details" can be simply artifacts from reseau marks.
But I made simple comparison with Titania topography obtained by photoclinometry from article
Large impact features on middle-sized icy satellites from Moore, Schenk, Bruesch, Asphaug and McKinnon (Icarus 171, 421-443)
and it looks very similar to their DEM of Gertrude regio.
This is cross-eye "stereo quaternion" made by same method. First pair is in principle same as my first cross-eye of Titania,
others are new for a little different perspective.
Two outer images are "original" (processed) images from Voyager, others are synthetic.
Edges are distorted, but I preserve them now for completeness (in cross-eye images, their aren't so disturbing).
EDIT: Anaglyph version is http://planets.wz.cz/uran/uranorig/tia_vg2_dam_003.png.
Wow! The anaglyph version looks almost like a hologram. The images appear to rotate slightly when you move your head from side to side. Beautiful work!
some new, cool infrared images of Uranus and Neptune
http://www.space.com/13086-photos-neptune-uranus-moons-infrared-images.html
One thing that got mentioned on twitter but not there was the obvious eccentricity of Uranus's rings. Pretty neat.
For anyone interested .I put together an artistic extrapolation based on the Keck and Hubble images
http://celestiamotherlode.net/catalog/show_addon_details.php?addon_id=1575
I just found the following information:
Professional observers reported a very bright cloud on Uranus, using the Gemini telescope. They need amateur confirmation:
http://www.universetoday.com/90393/observing-alert-bright-spot-on-uranus-reported/
The discovery was made over a month ago and it's strange that there is almost no mention to it in media (and even on the web) !
Best regards,
Marc.
Dear all,
I just bought the book "Uranus" edited by Bergstrahl, Miner and Matthews. With over 1000 pages, it is still "the bible" of the Uranian system. There are many data, pictures, mosaics and schemes not found anywhere else. Looking at the maps of the moons, I realized that there were still many important features without a name (especially on Miranda).
Just few examples:
the 340° chasma,
the South Pole Tangent chasma,
the Arden Concentric chasmata.
There are also many other interesting linear features as well as craters and basins deserving a name (not only on Miranda).
Most of the names were given in 1988. Three others were added in 1997.
I'm wondering about the rules to decide to name features. Will we have to wait the next mission to the Uranian system (20 years from now at best) to get some new ones ?
Best regards,
Marc.
Check out this website:
http://planetarynames.wr.usgs.gov/
You will see lists and maps of names throughout the solar system (only lists for the Uranian satellites so far), but also a lot of background information including naming themes, and a form for suggesting names.
You can suggest names, as anyone can, but typically they are not accepted unless there is a compelling reason such as a new mission (look for new names soon in the Gale crater area on Mars), a new scientific study (recent names on Mars include small dark-rayed craters, for instance, based on a recent study) or a forthcoming geological map.
I have made suggestions in the past, but never had any adopted!
Phil
Thanks Phil,
Maybe I will try to suggest some ! Who knows ?
Marc.
Greetings. Here are the present versions of my Uranian satellite maps with feature labels, starting with Miranda and Ariel:
And here's Umbriel assuming a 265 degree center longitude in Phil's map.
Little surprised that no one has commented on this:
http://www.astrobio.net/pressrelease/4694/uranus-aurora-glimpsed-from-earth
Very cool. Been waiting for something like this for a long time.
If the phenomena are transient presumably people will now be able to monitor more assiduously.
Neptune next?
P
Edit: I guess this could have gone in telescopic observations. But what the heck, its not like there are fleets of spacecraft heading out that way...
I only just noticed Steve's question about Pixie Chasma above - the Chasma is right underneath the label.
Phil
Keck observations bring weather of Uranus into sharp focus
http://phys.org/news/2012-10-keck-weather-uranus-sharp-focus.html
Wow. The resolution is incredible. It will be interesting to see the evolution of those features near the pole over the next few years. Cannot wait to see what they do with Neptune.
Yes, they really are amazing. I would like to see Ceres imaged like that now!
Phil
Wow, I cannot believe it ! Uranus as we never have seen it ! Looks a lot like Jupiter !
time to remap the above keck images and incorporate it into the Uranus map
old map - Artists concept
http://imgbox.com/acqp3kx9
getting any good data out of the voyager images is not easy
WOW!!! To me these may be the planetary images of the year 2012. I feel like I'm looking at a completely new planet. Of the two ice giants it has always been Uranus that seemed to be more different visually from Jupiter/Saturn but now it suddenly seems the opposite may be true. It looks remarkably similar to Saturn. It's not only the north polar region that looks similar to Saturn's south polar region - Saturn has scalloped bands as well.
I never stop wondering what Voyager 2 would have seen had it been able to carry a Galileo/Cassini style imaging system, i.e. a CCD camera with near infrared filters. Uranus is so much more active-looking at infrared wavelength than it is in visible light. This is a great example of the fact that planets that look visually bland are not uninteresting. They are just more difficult to study.
I have said it before and I'm going to repeat it ;-) : I want a Uranus orbiter or flyby mission in my lifetime.
I want a Uranus orbiter or flyby mission in my lifetime.
Bjorn
Don't recall if you were here 'back in the day' but we learned a 'Galileo' style orbital tour of Uranus with many close satellite flybys is possible since Uranus and it's entourage are scaled, so to speak, down model of Jupiter system.
It could be a very exciting mission.
Amazing images and amazing technical story. I remember from late 80's, that even in the biggest telescopes, we could see Uranus like small bluish disc nearly without any discernible details.
Then HST came and first nice images from outer Solar system. And now we have telescopes with adaptive optics, which can produce such sharp images.
And before us is new ELT era. So as everyone here, I want Uranus orbiter, but even without it, we can expect even better images in "near" future (~20's).
Just fooling around with images - and a big thankyou to the creators of these original images, obviously.
I have merged one of the spectacular new images with a true (-er) colour image released a while ago (it's the one with the dark spot - if you look closely you will see it faintly shining through, and there's a new dark spot in the new image as well, at a different latitude). Purpose - just to show the new details in a manner a bit closer to the expected colours of Uranus. Disclaimer - the colours of the cloud belts change over time and the two images will not really match properly. This is just for illustration purposes.
Phil
Tonight was the poster session where Larry Sromovsky was showing these images and I just about fell over when I saw them. Sromovsky was downplaying it, saying it was "easy" when you had adaptive optics on a 10-meter telescope with great seeing and high signal-to-noise. Easy for him to say Leigh Fletcher was standing next to me and saying "these are the greatest images of Uranus in the history of mankind. And womankind."
Incredible.... can hardly believe these are from ground based telescopes.
What beautiful mysterious worlds these ice-giants are!
Craig
Finally, "real" Uranus looks quite like the expectations previous to the Voyager flyby !
Impressive post-equinox atmospheric action on the formerly 'boring' Uranus from Keck...
http://www.keckobservatory.org/recent/entry/cosmic_matters_stormy_weather_on_uranus
P
Shortly after finishing the flyby anniversary mosaic of Neptune I started thinking about Uranus, got an interesting idea, started processing the Voyager 2 Uranus images and came up with this (two versions of the same image):
Nice view Bjorn - with a polar pentagon (or maybe hexagon).
I don't know if the polar pentagon/hexagon is a real feature or not but it might be real (or not...). Interestingly, it's not clearly visible in versions of these images where I don't correct for the wind speed. I'm now working on the violet filtered images. They show the areas near the pole better than the orange images do but everything else is more visible in the orange images. One of the Voyager 2 wind speed measurements is actually from violet images: The Voyager 2 measurement closest to the pole, at ~71 degrees south.
So far no results on the polar cap from the violet images, I just started processing them.
Here are two versions of an image from a stack of 8 violet filtered images:
Wow really nice Bjorn.
The latest Keck Observatory pictures of Uranus (August 2014) show massive storms:
http://www.keckobservatory.org/recent/entry/cosmic_matters_stormy_weather_on_uranus?utm_source=Keck+Nation&utm_campaign=3f6c6e6184-CM_Imke_Uranus&utm_medium=email&utm_term=0_aea15e0be5-3f6c6e6184-22182121
Uranus once looked dull but it really isn't - it's a very interesting planet. The problem is the thick hazes which make any features difficult to observe unless infrared imaging is used. There really is a lot of activity there and I'm starting to get the impression that if you count the number of active-looking features, storms, bright and dark spots etc. it might actually be more active than Neptune. I'm no expert here though so take this with a grain of salt (but it would be interesting to know if this is true).
But it turns out that the big, bright feature visible in the right image above is actually the biggest storm ever observed on Uranus, see e.g. http://www.keckobservatory.org/recent/entry/cosmic_matters_stormy_weather_on_uranus and http://www.space.com/26794-uranus-giant-storms-photos.html. In fact it's so big that it has been imaged by amateur astronomers. A movie by Anthony Wesley can be seen here:
http://www.acquerra.com.au/astro/gallery/other/20141002-151849/u20141002-storm-anim.gif
And his gallery of Uranus images is well worth visiting (other targets can also be seen at his website):
http://www.acquerra.com.au/astro/gallery/other/index.live
In addition, HST observed the storm in mid-October but as far as I know the images haven't appeared anywhere yet. It will be interesting to see them.
And here is an enhanced version of the images above. I processed it to reveal small scale features more clearly :
Voyager image processing magic by Erich Karkoschka:
http://uanews.org/story/clues-revealed-about-hidden-interior-of-uranus
Wow, just great. My favorite planet looks better and better.
By comparing these enhanced Voyager pictures with the Keck pictures, we can see that the southern hemisphere did not change much since 1986.
The wide and the narrow bright bands are present in both sets of pictures, with storms between them.
The narrow dark band close to the wide bright one is also present in both sets.
Erich Karkoschka's enhanced Voyager picture
Uranus by Keck
We have now good resolution for both hemispheres. Can't wait to see a new map !!
Regards,
Marc.
Record-breaking Storm Activity on Uranus in 2014
http://arxiv.org/pdf/1501.01309
P
A key quote:
Could it be that Uranus have a more quiet period when one of the poles face the sun, and increased activity when both poles face the sun and we get a temperature difference from the equator and the poles with weather systems and these storms? The energy from the sun is indeed weak, but even so, this activity have indeed increased as the planet turned so it cannot be ruled out it is part of the reason for this increased activity.
I'd always assumed that was exactly the working hypothesis. The planet's atmosphere is drastically different in appearance than it was during the V2 flyby, and the obvious major external change has been the angle of solar illumination.
The equatorial regions would generally be expected to have more dynamic activity than the poles. Sheer speculation, but I wonder if the addition of direct solar heating to them either increases atmospheric mixing or facilitates some sort of photochemical process, either or both of which act to clear the haze.
Wow. Keck AO does it again.
http://www.sciencedirect.com/science/article/pii/S0019103515002390
Even better if you have a subscription.
Let's hope for a mission, even a multi-tasked flyby, before we all fall off the perch.
P
Look at the equatorial band of scalloped clouds!
More astonishing AO imaging from Keck II and Gemini North. This blows my mind.
http://arxiv.org/pdf/1512.05009.pdf
Imagine what the ELT class scopes might offer!
Where's that Uranus orbiter!
Voyager Mission Celebrates 30 Years Since Uranus:
http://www.jpl.nasa.gov/news/news.php?feature=4827
And nobody knows how long we still have to wait until next mission to this amazing world !
http://photojournal.jpl.nasa.gov/jpeg/PIA01391.jpg
Today is the Voyager 2 Uranus 30 year flyby anniversary. Below are my recently reprocessed versions of the highest resolution Voyager 2 images of Titania and Oberon. They are from an unfinished image processing project I'm working on (Miranda, Ariel and Umbriel are unfinished and I might add color versions of Titania and Oberon).
First is Titania. The upper image is rendered from a sharpened stack of three polar maps. One additional image is available but it is too blurred to be useful for stacking. The original images were obtained on January 24, 1986 around 09:11 at a range of ~500,000 km.
The second one is from a stack of two maps. The original images were obtained on January 24, 1986 around 14:17 at a range of ~370,000 km.
..."not exactly detailed", but stunning nonetheless. Beautiful work.
A world that these images remind me of, visually, is Mercury. Obviously, the compositions are radically different, but they share a quality one doesn't see (often) in images of, say, the Moon, Callisto, or Rhea, which is that craters seem to excavate both dark and light material, depending in some way that may pertain to lateral variations in composition. And that indicates something rather interesting about primordial formation processes. So, it's interesting to see that on both Mercury, which is by far the solar system's most massive body without a multi-gigayear history of volatile and volcanic reworking of the surface, and these much smaller bodies with completely different composition.
Interesting comparison to Mercury. The albedo variations of the surface material are interesting, especially on Oberon where both dark and light material seems to have been excavated in several craters. The resolution is frustratingly low though and makes it difficult to tell exactly what is happening (I wonder if the Voyager 2 imaging sequence would have been designed with image stacking/superresolution in mind had those image processing techniques been common back in 1986).
On Titania dark stuff in craters is far more rare than on Oberon. However, Titania's chasm reminds me of Ariel, Charon and Tethys. Of course detailed comparisons are diffcult since Charon and Tethys have been vastly better imaged than Titania. Ariel has also been compared to Charon but even though Ariel is considerably better imaged than Titania the imaging coverage there is far worse than at Charon. We really need to revisit Uranus!
Sorry, I'm just finding this now. Excellent work, Bjorn. I think part of the differences between these reflect the fact that I did a little more to suppress noise, although this possibly obliterated marginal detail (but I thought it looked better). Here are my versions of these images.
A gif of the 1/23/1986 Titania phase angle coverage using violet and green frames for my fellow UMSFites. The green channel is synthetic.
Non-rotated version:
Not as clean looking as the first image in this thread, but here's my own quick, dirty, kinda bad take on a color Uranus with one ring. The color is OGB and the ring was exposed by stacking the OGB frames along with most of the other images from the same filter/exposure cycle, none of which were exposed for rings/faint objects (besides the atmosphere of course, which was obviously very faint out there). Since these cycles repeated as part of a movie sequence, one could technically create color ringed Uranus movies using real, simultaneously taken data.
The ring can actually be faintly seen in some normally exposed, uncombined images.
Lots of great stuff in this thread!
I didn't realize how stormy Uranus could be - it's too bad there wasn't more activity when Voyager was there, or that it wasn't sensitive to IR - it would have made for some striking images.
I also hope a Uranus orbiter will happen someday, but in the meantime the next-generation telescopes should be amazing - it's hard to believe this was taken from Earth!
If what you are asking for was easy it would have been done long ago. Because of time constraints, all the high resolution images were B/W. The color images were taken earlier, not just at lower resolution but also from a different direction. Overlaying the best color on the best B/W would need reprojection and would usually have an area which is not covered by color. Oberon might be the easiest one to do successfully. Artificial colorizing might give good results in the hands of a real artist like Damia Bouic.
Phil
I don't know on what schedule this might take place, but the new generation of larger ground based telescopes ought to be able to produce some impressive global maps of the uranian satellites at a resolution that will, to be sure, not match Voyager 2, but may be comprehensive and cover the entire surfaces with arbitrary spectral coverage.
It is particularly helpful that the four or five larger satellites are all co-located, so the same set of observations with no/little repointing can cover them all.
To speak to the capabilities, compare this image of Ganymede:
http://www.unmannedspaceflight.com/index.php?showtopic=8253
Uranus is about 4.3 times farther than Jupiter, but the ELT will have 7.9 times the aperture of the Hale Telescope that took that pictures, so the resolution per km will roughly double. Titania is about 1/3 the diameter of Ganymede, so the pictures of Titania, enlarged to the side of that Ganymede photo, will end up having about 1.5x worse resolution, which is still damned good. In fact, that will exceed the Voyager 2 resolution in many cases. And the ground-based telescopes can sit and wait for the uranian seasons to change. There are three telescopes in development that will radically (more than 2x) improve upon the largest existing telescopes.
Now, I'm sure these worlds aren't in anybody's top ten list of priorities, and I have no certain insights as to when they'll score some observation time, but it seems inevitable that such observations will eventually occur, and precede the next mission to arrive on the scene. The uranian satellites may even be among the higher priorities in the solar system, because telescopic mapping will not improve on Galileo/Europa Clipper/Cassini mapping of the major satellites of Jupiter and Saturn. Other worlds that could benefit from these capabilities will include Pallas, Juno, and Triton.
So lament not – the day of revelation (of the outer and smaller worlds) is coming.
Thanks for giving me hope. Can a quick colorization of this image of Miranda http://www.planetary.org/multimedia/space-images/uranus/voyager-2s-best-image-of.html image using the low res color data be done through? I'll attempt it myself, I just have very little experience with graphics editing and have only GIMP to use. I just feeling a color picture is more immersive in a "feel like being there" way and I don't wanna have a BW wallpaper and the color data for Miranda seem to be near uniform (basically it's all a very mild pinkish color). I'd be really thankful if someone did it, through I am gonna attempt it myself.
Here is my very quick and very dirty attempt using GIMP:
http://tinypic.com/r/akuz5c/9 using color from the NASA pic
http://tinypic.com/r/2zio48m/9 using color from the wallpaper pic
To be honest it sucks.
as an example of what phil posted ( post # 103 ) about needing to remap to add color and the LARGE amount of time needed to do it scientifically correct ( not a very fast job )
see my thread here
http://www.unmannedspaceflight.com/index.php?showtopic=8198
and this was a very fast and very quickly done example that would need about 8 or so more hours for a better job on just that ONE AREA
this dose take a lot of time to do right
i might have some time on sunday ? maybe
BUT!!!!! there will be NO!!! color band corection from the Orange,green,Blue,violet , and UV images other than a guess ( NO MATH INVOLVED)
nor will i have time ti unwarp the images do to the lens distortion
the reasue marks ann lens distortion lines can be removed easily , so can missing lines of the image
making control nets are VERY time consuming , but some minor warping in the mapping can be done with just 3,4,or5 points and not 100+ points
but that is a very basic realigning of the remaped color filter images
for a very fast done sets for
Ariel , Umbriel , Titania , Oberon , Miranda,
now for the "rocks" in orbit there are spectragraph sets of data for the over color
but even some very fastly done color images of the major moons WILL take time
a few days if not a week or more
and right now i really do not have much free time so 2 to 3 hours at most a night a few nights a week
will take some time
Here's my attempt at processing a composite image from the color sequence and ring mosaic taken on January 23, 1986. I have done some work to bring out some of the cloud present in the longer-wavelength images, primarily by differencing the orange wavelength filter (where the upper level haze is most transparent to Voyager's camera system) with the violet filter (which is dominated by haze scattering). I modified the differenced image a little to produce a synthetic "red" channel. In addition, it was partially used as a luminance channel to help the color variations stand out a little more.
Although the overall appearance is still relatively bland, a south polar and temperate cloud belt are visible. It also looks like the cirrus cloud that is visible in most processings of this image set appears to be correlated to the storm system that Erich Karkoschka found in stacked images back in 2014.
There were numerous stars in the ring mosaic. I suspect that a lot of these are moons, but none matched the ephemerides positions in OPUS' Uranus Viewer so I can't say for sure what's what.
https://flic.kr/p/244F8LF
https://flic.kr/p/244F8LF
Found this really cool 5K high resolution map of Miranda by Robin Charles Gilbert. While there are other maps of Miranda, I have yet to see any others that really showcase the full resolution of the Voyager images quite like this one.
http://www.robingilbert.com/blog/2017-08-20-atlas-of-miranda/
When a Uranian pole is pointed more or less at the sun, then the potential uranusshine on a moon would be on the ~1/4 of the surface that can, at that time, see the planet but not the Sun. It's a considerably worse case than with Jupiter or Saturn.
That said, it was a challenge for Voyager to take images of the moons even in sunlight, since the cameras were spec'ed only for Jupiter and Saturn. The light of a half Uranus would be orders of magnitude less than sunlight, so it seems far out of the realm of possibility for those cameras.
I definitely committed the sin of posting based on seconds of mental arithmetic rather than something firmer, and Ted's images visibly contradict my guesstimates, so I got a little more serious about it.
First, the moons obviously differ in distance from Uranus, so the light they receive from it vary in this proportion.
If Oberon = 1 unit of luminance from Uranus, the others receive:
Miranda 20.5, Ariel 9.3, Umbriel 4.8, Titania 1.8.
Uranus is huge in each of their skies (22.7° at Miranda!) but seen in a half phase, which I estimate to be 1/4 of the light of a full Uranus, based on hard data from Venus, which is likewise a bland cloudy (and lambertian) ball. Of course, the sunlight at Uranus is 1/360 of that at Earth, but that is relative if we are comparing the sunlit portions of the moons with the uranus-lit.
In a nutshell, the uranus-shine is much brighter than, say, earthshine on the Moon in a given orbital configuration, as a fraction of sunlight at the respective distances from the Sun. In this respect, the half uranus shine on each moon is this ratio of full earthshine on a slender crescent Moon: Miranda 38, Ariel 17.5, Umbriel 9, Titania 3, Oberon 2. In absolute terms, the uranus shine is much dimmer than earthshine on the crescent Moon (divide all of those by 360).
What I fundamentally did not take into account is that the need to slew the spacecraft, a fact I'd known anecdotally, was only necessary for closer images. Full-disc images taken from a distance did not have such a requirement and the exposures were quite long – about 15 seconds. As you can see by snapping an image of the earthshine Moon with your pocket phone camera, getting earthshine in an image with the crescent is not so hard even with a short exposure and 15 seconds at Uranus (for, say, Oberon) is about the same at 0.1 seconds exposure of the Moon.
Note that with the Moon, it is difficult to capture earthshine on a photo of the half Moon or fuller phases because the glare of the sunlit portion destroys the earthshine portion. At Uranus, with those ratios of 2 to 38, that difficulty is overcome.
Now as for why any given image that seems like it might have shown uranusshine but did not, I would want to check on the albedo of that moon, the uniformity of albedo across its surface, and the exposure duration.
I hope this makes amends for my hasty and incorrect estimates before.
Since this is the 20th anniversary of the discovery of planetshine on the Uranian satellites (reported at LPSC in March 2001, abstract attached here), it's good to get back to it again.
This link:
https://www.planetary.org/articles/1362
discusses the situation in more detail with some of Ted Stryk's processed images.
As Voyager 2 approached the Uranian system the moons were spread out around it and viewed at closest approach from different directions. If you get lucky the part of the moon lit by planetshine is going to be visible at closest approach, and that was the case for Ariel. For the others, either the part illuminated by Uranus was facing the other way or it was only seen as a very thin crescent and at lower resolution. Remember that the idea of viewing the 'night' side in reflected light had not been considered by the Voyager science team (or maybe considered but rejected), so imaging was not undertaken with a view to capturing these scenes and anything we got was serendipitous.
Cassini took full advantage of this discovery and we got spectacular results that significantly increased coverage of many moons.
Phil
stooke_lpsc_32_satellites_1074.pdf ( 130.24K )
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Thanks, Phil. I found a diagram showing how the uranian system was oriented at the time of the V2 flyby, but it's hard to read a 4-dimensional reality as rendered in 2 dimensions.
For each moon, at the time of V2, there was effectively a division of the moon into quadrants. Two were in sunlight. One was in uranusshine. One was in neither. Uranusshine imagery would depend upon whether or not V2 ever could see that uranusshine quadrant and furthermore took an image at that time.
Saturn and Neptune in certain ways are each more favorable for this – you can get the night sides of the moons receiving a full planetary shine rather than ~1/4 brightness. Also, Saturn is even more huge in the skies of its moons than Uranus is for its moons.
Yes, all systems are equal if visited at their respective equinoxes. Temporarily, there is no difference in observation opportunities.
As noted earlier, the capabilities of ground-based telescopes will improve dramatically in the next decade, and then there's no concern about timing. The coming telescopes should be able to provide resolution for Triton (and Neptune's other moons) about as good as we see of Ganymede in this image:
https://sites.astro.caltech.edu/palomar/current/20170909_wallace.html
And for the uranian moons, the resolution will be about 50% sharper.
I wonder how well the JWST will be able to resolve these moons.
I doubt that there will be anything like this observable from Earth. We don't see it at Callisto or Iapetus. We see Mars's winter cap emerge from springtime and thaw. Titania has a trace atmosphere at best.
The JWST will have about the same resolution as HST. Despite the larger aperture, longer wavelengths limit resolutions. Ground based telescopes are going to blow away the HST, and therefore JWST as well, in terms of resolution. Of course, they will be more limited in terms of observation opportunities, but with Uranus's moons, a total of about a dozen observations for each spread out over a couple of decades will completely begin and end the mapping observations that a given instrument is capable of.
The JWST's aperture will be 6.5 m.
EELT's aperture will be 39.3 m.
WE NEED A URANUS ORBITER TO go to URANUS'S MOONS
ASAP (when its in equinox)
UMSF's own Ian R making https://www.space.com/uranus-voyager-hidden-data-ring-mystery?fbclid=IwAR0hZBzONWAfDV90-zpjIwmiCHxRQm3DlqNrxG4fxDDsJAaUKbuVFrEmp3c in old Voyager 2 data, and also making space news headlines!
Outstanding work. Your title will be upgraded shortly.
Why, thank you, kind sir!! Since the article neglected to show the image itself, here it is along with an explanatory schematic:
Not the first "new images show" article that doesn't show the new images, unfortunately. Thanks for sharing!
Processed a superior version of the image I cobbled together last year. Now the brightest part of the Epsilon ring (at the 9 o'clock position) is more much evident:
> Scientists originally missed the find because the reddish dusty ring closest to Uranus wasn't visible in any individual image — Regan had to combine a host of images together for the feature to appear. "He took hundreds of images, stacked them together, to produce this image of the Uranian system," Hedman said. "This is the most comprehensive view of the zeta ring that exists and we didn't know it was in the Voyager data for decades."
Very cool, Ian!
Does anybody with a subscription to Sky and Telescope know if the recovery of the Zeta ring was reported in any of the issues published late 2022 / early 2023?
It was reported in the February 2023 issue (page 11).
Thank you Bjorn, Ian and Emily! See here https://is.gd/UranusRings
Uranus' polar cyclone imaged
https://phys.org/news/2023-05-scientists-polar-cyclone-uranus.html
P
And now on the ArXiv.
https://arxiv.org/pdf/2305.15521.pdf
P
Webb at it again with the 7th planet:
https://webbtelescope.org/contents/news-releases/2023/news-2023-150
The annotated wide field is especially stunning, fabulous sense of depth and scale
with those distant galaxies in the far far background, but also an active atmosphere
and a lot of moons visible on the closeup
P
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