IPB

Welcome Guest ( Log In | Register )

6 Pages V  « < 3 4 5 6 >  
Reply to this topicStart new topic
Uranus System Imaging
Phil Stooke
post Apr 16 2012, 11:44 AM
Post #61


Senior Member
****

Group: Members
Posts: 5846
Joined: 5-April 05
From: Canada
Member No.: 227



I only just noticed Steve's question about Pixie Chasma above - the Chasma is right underneath the label.

Phil



--------------------
... because the Solar System ain't gonna map itself.
Go to the top of the page
 
+Quote Post
morganism
post Oct 17 2012, 11:49 PM
Post #62


Newbie
*

Group: Members
Posts: 17
Joined: 24-August 12
Member No.: 6610



Keck observations bring weather of Uranus into sharp focus

http://phys.org/news/2012-10-keck-weather-...harp-focus.html


--------------------
Thomas Gold was probably right about a iceball Mars.....
Go to the top of the page
 
+Quote Post
Ken90000
post Oct 18 2012, 02:41 AM
Post #63


Junior Member
**

Group: Members
Posts: 53
Joined: 8-November 06
From: Indiana, USA
Member No.: 1337



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.
Go to the top of the page
 
+Quote Post
Phil Stooke
post Oct 18 2012, 03:32 AM
Post #64


Senior Member
****

Group: Members
Posts: 5846
Joined: 5-April 05
From: Canada
Member No.: 227



Yes, they really are amazing. I would like to see Ceres imaged like that now!

Phil



--------------------
... because the Solar System ain't gonna map itself.
Go to the top of the page
 
+Quote Post
MarcF
post Oct 18 2012, 08:18 AM
Post #65


Member
***

Group: Members
Posts: 182
Joined: 16-May 06
From: Geneva, Switzerland
Member No.: 773



Wow, I cannot believe it ! Uranus as we never have seen it ! Looks a lot like Jupiter !
Go to the top of the page
 
+Quote Post
JohnVV
post Oct 18 2012, 09:00 AM
Post #66


Member
***

Group: Members
Posts: 547
Joined: 18-November 08
Member No.: 4489



time to remap the above keck images and incorporate it into the Uranus map
old map - Artists concept


getting any good data out of the voyager images is not easy
Go to the top of the page
 
+Quote Post
Bjorn Jonsson
post Oct 18 2012, 03:05 PM
Post #67


IMG to PNG GOD
****

Group: Moderator
Posts: 1526
Joined: 19-February 04
From: Near fire and ice
Member No.: 38



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.
Go to the top of the page
 
+Quote Post
tasp
post Oct 18 2012, 04:15 PM
Post #68


Member
***

Group: Members
Posts: 885
Joined: 30-January 05
Member No.: 162



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.
Go to the top of the page
 
+Quote Post
machi
post Oct 18 2012, 05:35 PM
Post #69


Member
***

Group: Members
Posts: 662
Joined: 27-February 08
From: Heart of Europe
Member No.: 4057



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).


--------------------
Go to the top of the page
 
+Quote Post
Phil Stooke
post Oct 19 2012, 01:35 AM
Post #70


Senior Member
****

Group: Members
Posts: 5846
Joined: 5-April 05
From: Canada
Member No.: 227



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

Attached Image


--------------------
... because the Solar System ain't gonna map itself.
Go to the top of the page
 
+Quote Post
elakdawalla
post Oct 19 2012, 02:44 AM
Post #71


Bloggette par Excellence
****

Group: Admin
Posts: 4524
Joined: 4-August 05
From: Pasadena, CA, USA, Earth
Member No.: 454



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 smile.gif Leigh Fletcher was standing next to me and saying "these are the greatest images of Uranus in the history of mankind. And womankind."


--------------------
My blog - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
Go to the top of the page
 
+Quote Post
belleraphon1
post Oct 19 2012, 07:44 PM
Post #72


Member
***

Group: Members
Posts: 741
Joined: 29-December 05
From: NE Oh, USA
Member No.: 627



Incredible.... can hardly believe these are from ground based telescopes.

What beautiful mysterious worlds these ice-giants are!

Craig
Go to the top of the page
 
+Quote Post
MarcF
post Oct 20 2012, 10:52 AM
Post #73


Member
***

Group: Members
Posts: 182
Joined: 16-May 06
From: Geneva, Switzerland
Member No.: 773



Finally, "real" Uranus looks quite like the expectations previous to the Voyager flyby !

Go to the top of the page
 
+Quote Post
antipode
post Aug 8 2014, 07:44 AM
Post #74


Member
***

Group: Members
Posts: 153
Joined: 1-October 06
Member No.: 1206



Impressive post-equinox atmospheric action on the formerly 'boring' Uranus from Keck...

http://www.keckobservatory.org/recent/entr...ather_on_uranus

P
Go to the top of the page
 
+Quote Post
Bjorn Jonsson
post Sep 13 2014, 08:57 PM
Post #75


IMG to PNG GOD
****

Group: Moderator
Posts: 1526
Joined: 19-February 04
From: Near fire and ice
Member No.: 38



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):

Attached Image
Attached Image


I think these may be the most detailed Voyager 2 global images of Uranus I have ever seen (but they are far inferior to recent groundbased images).

The processing idea came from the description of the processing of these images of Uranus:

http://www.planetary.org/blogs/emily-lakda...eck-photos.html

In short, I used 6 orange and 6 green filtered images that I reprojected to simple cylindrical projection, removing (or at least greatly reducing) the effects of global illumination on the fly. This was sufficient to correct for Uranus' rotation but since the images were obtained over a period of ~5 hours this was not sufficient - it's necessary to correct for Uranus' fast east/west zonal winds as well. To do this I found a profile (and I think it's a very recent and up to date one) showing Uranus' zonal wind speed as a function of latitude. I used this to correct the individual cylindrical maps by shifting each image row in the east-west direction. I then stacked the 12 maps, rendered an image and then greatly increased the contrast and visibility of various features. In the left image I first enhanced the contrast and then sharpened the image with an unsharp mask. In the right one I first enhanced the contrast, then suppressed large scale brightness variations with a high pass filter and then further increased the contrast.

The source images were obtained on January 17, 1986 between 14:19:10 and 19:35:10. At this time Voyager 2 was ~9 million km from Uranus.

This is experimental work in progress and it is probably possible to get better results. A day earlier, a longer sequence of images was obtained but it took a longer time; I strongly suspect that there is a limit to how long the time can be if you want good stacking results but I don't know what this limit is. One interesting processing artifact that may occur if the zonal wind profile I'm using is inaccurate is that bright or dark features get too elongated in the east/west direction but I don't think this is a significant issue here. Interestingly, even if this happen the feature's longitudinal position can be accurately estimated as the average of the west and east edges of the feature, as pointed out in a very interesting article by Sromovsky et al. in Icarus 203 (1): 265286 (2009). EDIT: It's actually in Fry et al., Astronomical Journal vol. 143, no. 6, June 2012 where this is pointed out (the Sromovsky et al. article is very interesting too though).

There is considerable noise in the above images but it should be fairly obvious which features are real and which ones are noise and/or image processing artifacts. All of the obvious bright spots are definitely real and all of the narrow bright/dark east-west cloud belts (there are several of these) should be real as well. The dark, "partial cloud belts" near the bright spots are real as well. Another faint "partial belt" to the right of the dark polar cap may be real but I'm not sure. Some of these features are completely new to me.

With the benefit of hindsight, it is apparent that the best way for Voyager 2 to image Uranus might have been to obtain a few big sequences of orange-only images (orange images show the biggest amount of detail) in as short a time interval as possible, maybe using the tape recorder to speed things up due to the low bit rate possible from Uranus. This would have made the stacking results better. But of course there was absolutely no way to know this back in 1986.

I think the images above might hint at what additional details Voyager 2 could have seen had it been able to carry a Galileo/Cassini-style imaging system with near infrared filters. And they may hint at what a future spacecraft might see if it arrives when the illumination geometry is comparable to what it was in 1986.

Uranus' is *not* an uninteresting planet, it's simply more difficult to observe than the other giant planets due to low contrast and hazes. In my opinion it's at least as interesting as e.g. Neptune - and significantly different from it.
Go to the top of the page
 
+Quote Post

6 Pages V  « < 3 4 5 6 >
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 20th December 2014 - 05:10 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.