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PostPosted: Thu, 29-11-12, 19:46 GMT 
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Hi arctodus.
I downloaded your last release, and really the result is way better.
But I noted some strange things in the layers during rotation, so I gave a look and found what shown in these two images:

Image

Image

There is a wide gap between the horizontal extremities.
Using Photoshop Filter ->Other -->Move I matched the original texture extremities, avoiding so the wide gaps present in the first 7 ones.
Now in my opinion the result is much better.
Just a note: there is still a little defect, shown in this image:

Image

Any idea on how to eliminate it? :roll:

Thanks a lot for your work, arctodus, very enjoyable.
Bye

Goofy :D

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PostPosted: Fri, 30-11-12, 14:53 GMT 
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Hi all,

after some research as to the published scientific information about the differential speeds of the various cloud areas of Jupiter, I think this project should be largely started from fresh. This way a result of scientific standing may be achieved.

This is the level where I would get actively interested...

Here are some crucial data & infos:

Some partial quotes from
http://www.nasa.gov/centers/goddard/mul ... phere.html

Analysis of data at many wavelengths shows that the white regions have higher thicker, clouds than the redder regions.
...
The clouds in the reddish brown "belts" are deeper, covered by thick smog-like haze.


These belts and zones are also lined up with Jupiter's strong wind field, which may drive the cloud formation. The winds alternate from eastward to westward with latitude and can top 150 m/s (325 mph). An interesting aspect is that the winds are extraordinarily constant: the wind speed at a given latitude varies very little over time.
Most importantly, here is an overlay of the actual wind speeds as function of latitude!
Image
The vertical black line equals zero wind speed. The highest velocities exceed 150 m/sec (~540 km/h).

Image

This color movie from NASA's Cassini spacecraft refers to a stationary sphere as jupiter's atmosphere evolves with time. The clip spans 24 Jupiter rotations.

Here is the corresponding flat version:

Image

There are further bw-animations, like

Image

and the flat one

Image

all from this NASA link
http://www.nasa.gov/centers/goddard/mul ... llery.html

++++++++++++++++++++++++++++++++++
These animations roughly correspond to a reference frame where the great red spot is stationary. If the proper rotation speed is added, it becomes apparent that the cloud speeds of the above add-on by Max are not correct and require revision.

Altogether, there is enough quantitative scientific information allowing a rather precise modelling of Jupiters dynamical atmosphere!
++++++++++++++++++++++++++++++++++

Fridger


Last edited by t00fri on Sun, 02-12-12, 9:06 GMT, edited 1 time in total.

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PostPosted: Fri, 30-11-12, 15:13 GMT 
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These animations are so frakking cool, that one cannot avoid dreaming about warping *video* around a planet to see them in Celestia...


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PostPosted: Fri, 30-11-12, 15:24 GMT 
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abramson wrote:
These animations are so frakking cool, that one cannot avoid dreaming about warping *video* around a planet to see them in Celestia...


Precisely, Guillermo!

Since the above NASA movies are just animated GIFs the splitting into layers is already done for us: If you load anyone of these animated GIF files into GIMP you have the various layers directly at your disposal! Wrapping them around Jupiter is indeed a possibility...

And therefore, I think it is very worthwhile to try and input all available scientific info into such an animated rendering.

Moreover graphically, there is room for significant improvements as concerns a proper subdivision of the various moving cloud belts into layers corresponding to one particular speed, each. Finally, a proper compression (DXT3) should be performed in order to make the package faster and thus smoother also for slower hardware.

Fridger


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PostPosted: Sun, 02-12-12, 17:20 GMT 
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Hi all,

meanwhile I was able to collect all scientific data required for a scientifically correct multi-layer rendering of Jupiter's zonal cloud flows in Celestia(.Sci).

As to sharing the zonal flow data in tabular form, there is unfortunately the essential problem that most scientific data in this field are NOT freely available! Personally, I am lucky that I have complete access to the journals in question through the network of my laboratory.

But clearly, I am not allowed to publish these articles neither in total nor in part.

Having decades of experience in scientific computing, I have found a workaround that allows other people interested to work on this project, to use the essential flow data without accessing data tables in the costly journals.

Starting point is the above overlay of the zonal flow data on a display of Jupiter in spherical projection. What is required, however, is the zonal velocity profile as function of latitude, rather than of sin( latitude ) as implied in the spherical projection overlay!

The resulting velocity profile may then be overlaid on a Jupiter texture in simple cylindrical projection. The next step is then a splitting of the texture into layers of corresponding velocity flow, etc...

What I (quickly) did is this:

1) With a few GIMP tricks, I extracted the overlaid zonal velocity graph from its spherical Jupiter texture background in this public NASA image

Image
(see also above: http://forum.celestialmatters.org/viewt ... 9&start=16)

2) The resulting plot was converted into a POSTSCIPT-2 file and the data read off into a text file with highest possible precision by means of some specialized scientific software (gv-readplot). The resulting tabular data were read into MAPLE where they could easily be processed further:

I replotted the read-in numerical data which looks like so:
Image

As a check, this plot can be overlaid on the GIMP-extracted overlay plot above and proves very accurate. Note, the ordinate in this plot is proportional to sin( latitude ) NOT to latitude as needed. However, within Maple a corresponding replot is very easy and looks like this

Image

where now the ordinate is latitude in degrees. As you can see by comparison, the image appears now stetched at latitudes closer to the poles due to the applied re-mapping sin(latitude) = y => latitude = arcsin(y).

I made TWO final checks with these reprocessed data:

1) An overlay on the Jupiter texture in simple cylindrical projection:

[Click on image for larger size]
Image
In reality I used a 4k true-color texture from Cassini, here I have reduced it to 1k.
The agreement of the velocity profile with the above spherical projection is very good!

2) I compared the result to the NON-free data (involving latitude in tabular form) with excellent agreement.

Here you may download the tabular data (rel. zonal speed, latitude[degrees]), corresponding to the red curve above:
http://www.celestialmatters.org/users/t00fri/files/jupiter_zonal_flow_flat.txt.zip
This text file contains 213 data points, i.e. a high-resolution tabulation of the required data.

This way I was able to extract the desired data from a public NASA image without taking recourse to the NON-free journal articles.

I hope someone can make use of the results ;-)

Fridger


Last edited by t00fri on Sun, 02-12-12, 18:39 GMT, edited 1 time in total.

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PostPosted: Sun, 02-12-12, 18:07 GMT 
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Hi all,

at last I found a graph that is publicly accessible and shows impressively the surprising constancy of the zonal velocity flow over a long time period: from Voyager 2 to Cassini!

Image
The plot is from
http://pubs.giss.nasa.gov/docs/2003/2003_Porco_etal.pdf

These data may be directly compared to the ones reprocessed in my previous post.

Fridger


Last edited by t00fri on Wed, 05-12-12, 20:35 GMT, edited 1 time in total.

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PostPosted: Sun, 02-12-12, 23:34 GMT 
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Hey, Max. Nicer. The black blotches have disappeared in my rendition, and I now see the same that you show in the video. Looks very realistic!

There is however still an artifact, some vertical discontinuities that depend on distance and orientation, it seems. They can even be seen in your video, during the first seconds, close to the center, over the light equatorial zone. I don't know what they are, there is nothing like that in the pngs.

Guillermo

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 Post subject: re
PostPosted: Mon, 03-12-12, 0:56 GMT 
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nice but you might want to fix the -180.0 / 180.0 line
here is a 1024 px offset
Image

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 Post subject:
PostPosted: Mon, 03-12-12, 10:39 GMT 
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Sorry but I have a doubt: given that Guillermo Abramson and John Van Vliet in the last two posts on 02-12-12 write about the same problems I pointed with my message on 29-11-12,20, I have the doubt that this message is not visible in the forum. :shock:
Can you confirm, please?
It contains three images, 2 of the gap at 1024 pixel and one about the defects in the Jupiter center.
Thank you.

Goofy :D

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 Post subject:
PostPosted: Mon, 03-12-12, 14:32 GMT 
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Goofy wrote:
Sorry but I have a doubt: given that Guillermo Abramson and John Van Vliet in the last two posts on 02-12-12 write about the same problems I pointed with my message on 29-11-12,20, I have the doubt that this message is not visible in the forum. :shock:
Can you confirm, please?
It contains three images, 2 of the gap at 1024 pixel and one about the defects in the Jupiter center.
Thank you.

Goofy :D


Goofy,

I can confirm that your post is very well readable and that I have read it some days ago. It was immediately obvious to me that the reason for these "joining" artefacts around the +180 deg and -180 deg ends of the texture is what John pointed out somewhat later in his post. If one has dealt a lot with textures, such phenomena are VERY familiar indeed.

Fridger


Last edited by t00fri on Mon, 03-12-12, 14:37 GMT, edited 1 time in total.

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 Post subject:
PostPosted: Mon, 03-12-12, 16:29 GMT 
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Nice to know it is readable, Fridger, thank you.
Bye

Goofy :D

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 Post subject:
PostPosted: Mon, 03-12-12, 17:18 GMT 
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Here is a public display of the layers of Jupiter's atmosphere. It is useful for modeling the banded layers for Celestia(.Sci).

Image
+++++++++++++++++++++++++
Caption
The vertical structure of Jupiter’s atmosphere. Jupiter’s clouds are arranged in three main layers, each with quite different colors and chemistry. The colors we see in photographs of the planet depend on the cloud cover. The white regions are the tops of the upper ammonia clouds. The yellows, reds, and browns are associated with the second cloud layer, which is composed of ammonium hydrosulfide ice. The lowest cloud layer is water ice and bluish in color. However, the overlying layers are sufficiently thick that this level is not seen in visible light.
++++++++++++++++++++++++

Since the planet lacks a solid surface to use as a reference level for measuring altitude, the top of the troposphere is conventionally taken to lie at 0 km.

The whole article, where this image is from, is also quite instructive:
http://astronomy.nju.edu.cn/~lixd/GA/AT ... T41102.htm

Fridger


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 Post subject: re
PostPosted: Mon, 03-12-12, 18:02 GMT 
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Hi
i look at A LOT of maps
and in the past an EXTREMELY LARGE number of images
I worked in photofinishing for many many years.
( color and black and white darkrooms)
-- yes with FILM that is in a camera ---

As a result the VERY VERY FIRST thing i "see" is technical
THEN the second is composition and image subject

Some things just stand out

i like the maps , but the mismatched ends are noticeable

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 Post subject:
PostPosted: Mon, 03-12-12, 21:38 GMT 
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Goofy wrote:
Sorry but I have a doubt: given that Guillermo Abramson and John Van Vliet in the last two posts on 02-12-12 write about the same problems I pointed with my message on 29-11-12,20 [...]
It contains three images, 2 of the gap at 1024 pixel and one about the defects in the Jupiter center.


Goofy:

The problem I mentioned in my message of 02-12-12, 21:34 is indeed the same that you called "little defect" and showed in your message of 29-11-12, 17:46. I wanted that Max knew that his latest version (which was announced after your message) still had this problem

G


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 Post subject:
PostPosted: Mon, 03-12-12, 22:40 GMT 
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Sorry Guillermo, I missed you was speaking of a following version.
My fault. :oops:

BTW, doubling all cloud layers heights solves the problem, no more defects at any distance (dunno why).
Bye

Goofy :D

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