Closeups of Saturn's Rings - 3 versions

Tips for creating and manipulating planet textures for Celestia.
Avatar
Topic author
Chuft-Captain
Posts: 1767
Joined: 18.12.2005
With us: 13 years 7 months

Closeups of Saturn's Rings - 3 versions

Post #1by Chuft-Captain » 22.05.2013, 21:49

(Click the images for full-size...)

A:
rings closeup A.jpg

B:
rings closeup B.jpg

C:
rings closeup C.jpg

Preferences?
Comments?
Last edited by Chuft-Captain on 01.10.2016, 00:47, edited 1 time in total.
"Is a planetary surface the right place for an expanding technological civilization?"
-- Gerard K. O'Neill (1969)

CATALOG SYNTAX HIGHLIGHTING TOOLS LAGRANGE POINTS

Avatar
Goofy
Posts: 240
Joined: 30.08.2011
With us: 7 years 10 months
Location: Italy

Re: Closeups of Saturn's Rings - 3 versions

Post #2by Goofy » 23.05.2013, 17:00

Hi Chuft-Captain.
Your ring textures are interesting, and I would like to check the B and C with Cassini's originals.
Will you upload them somewhere, please?
Bye

Goofy :D
"Something is always better than nothing!"
ASUS G75VX4007H- Intel i7 3630QM, 2.4 GHz-SSD 250GB+SSD 1TB, SATA 3-32GB DDR3 1600 MHz- Nvidia GeForce GTX 780MX 3 GB

Avatar
t00fri
Developer
Posts: 8772
Joined: 29.03.2002
Age: 17
With us: 17 years 3 months
Location: Hamburg, Germany

Re: Closeups of Saturn's Rings - 3 versions

Post #3by t00fri » 23.05.2013, 20:10

Good Saturn rings are not easy!

About 5.5 years ago, I made a nice texture for the lit side of the rings in high resolution (Ciclops data). See here the discussion from 3.5 years ago:
http://www.celestiaproject.net/forum/viewtopic ... 80&start=1
and about 5.5 years ago, when it all started:
viewtopic.php?f=2&t=11559&st=0&sk=t&sd=a&hilit=saturn+rings&start=19

The transparency across the rings (texture's alpha channel!) is determined and adjusted from earthbound observation of the passage of some star of known luminosity across the rings. Somewhere I have the citation of this amazing paper...

So far the unsatisfactory part concerns the unlit side of the rings that looks rather dull black with my texture. ChrisL made some shader experiments at the time (see quote above) to improve the view. In any case some hightech means are required to get a satisfactory result.

Fridger
Image

Avatar
Topic author
Chuft-Captain
Posts: 1767
Joined: 18.12.2005
With us: 13 years 7 months

Re: Closeups of Saturn's Rings - 3 versions

Post #4by Chuft-Captain » 23.05.2013, 23:01

Goofy,
It was a little bit of a trick question...
B is a crop of the NASA composition, here: http://www.nasa.gov/mission_pages/cassini/multimedia/pia06193.html
A is the 1.6.1 default 1K texture, from a similar viewpoint in Celestia,
and C is my 4K version.

So you can compare A and C directly with the Cassini version (B).

t00fri wrote:The transparency across the rings (texture's alpha channel!) is determined and adjusted from earthbound observation of the passage of some star of known luminosity across the rings. Somewhere I have the citation of this amazing paper...
For this first cut, the transparency in [C] is based on: data from the occultation of 28 Sgr.
I would be interested to read that paper if you can track down the reference. (Although the alpha channel is the least of the problems at this point.)

So far the unsatisfactory part concerns the unlit side of the rings that looks rather dull black with my texture. ChrisL made some shader experiments at the time (see quote above) to improve the view. In any case some hightech means are required to get a satisfactory result.
I agree. For the sake of this exercise, I took the color channels from the un-illuminated side of the rings: http://photojournal.jpl.nasa.gov/catalog/PIA08389 which also gives unsatisfactory results (but in the opposite circumstances). As you suggested, there is no easy solution to this, only compromises. (short of more sophisticated shaders).

For further comparison, here are the views from Cassini on the date of the NASA imagery (06 Oct 2004). Again (B) is the NASA composite for comparison with the view in Celestia using (A) the 1K default texture, and (C) my new 4K version. (The issues are more obvious in these images...)

A:
Cassini-A.jpg

B:
Cassini-B.jpg

C:
Cassini-C.jpg
Last edited by Chuft-Captain on 01.10.2016, 00:48, edited 1 time in total.
"Is a planetary surface the right place for an expanding technological civilization?"
-- Gerard K. O'Neill (1969)

CATALOG SYNTAX HIGHLIGHTING TOOLS LAGRANGE POINTS

Avatar
t00fri
Developer
Posts: 8772
Joined: 29.03.2002
Age: 17
With us: 17 years 3 months
Location: Hamburg, Germany

Re: Closeups of Saturn's Rings - 3 versions

Post #5by t00fri » 24.05.2013, 00:06

CC,
I am quite sure it was the 28 Sgr paper you mentioned. It's also cited in the Celestia-README. Unfortunately most people need to pay 31$ for reading it. Didn't find a free option. I can read it through my laboratory though, but no sending around, of course.

Fridger
Image

abramson
Posts: 404
Joined: 22.07.2003
With us: 15 years 11 months
Location: Bariloche, Argentina

Re: Closeups of Saturn's Rings - 3 versions

Post #6by abramson » 24.05.2013, 02:24

Someone over at Arizona has it on line, though :wink:
http://www.lpl.arizona.edu/~umpire/professional/papers/1067a.pdf

Avatar
Topic author
Chuft-Captain
Posts: 1767
Joined: 18.12.2005
With us: 13 years 7 months

Re: Closeups of Saturn's Rings - 3 versions

Post #7by Chuft-Captain » 25.05.2013, 21:24

Thanks for sharing that link Guillermo. :)
"Is a planetary surface the right place for an expanding technological civilization?"
-- Gerard K. O'Neill (1969)

CATALOG SYNTAX HIGHLIGHTING TOOLS LAGRANGE POINTS

Avatar
Topic author
Chuft-Captain
Posts: 1767
Joined: 18.12.2005
With us: 13 years 7 months

Re: Closeups of Saturn's Rings - 3 versions

Post #8by Chuft-Captain » 31.05.2013, 07:45

The latest iteration, using color channels from the illuminated side:
Cassini-D-i.jpg

rings closeup D-i.jpg
"Is a planetary surface the right place for an expanding technological civilization?"
-- Gerard K. O'Neill (1969)

CATALOG SYNTAX HIGHLIGHTING TOOLS LAGRANGE POINTS

Danny Lorraine II

Post #9by Danny Lorraine II » 30.05.2018, 01:09

where can i get those textures? i might need them for my celestia . thanks


Return to “Textures”

Who is online

Users browsing this forum: 1 guest