Saturn blue E and reddish G rings

[t00fri]

Well, I am reading this additional Saturn ring business here since a few days. Could someone give me some scientific background reference whether these weak blue and red and... rings are visible for the naked eye!?

I am quite sure they are NOT!

So far the rules of the game in Celestia are that we ignore wavelength filters and essentially concentrate on phenomena that are visible without special instruments...

Bye Fridger

Of course, they are not visible with the naked eye.
What is your problem?
This is an add-on.
You don't like it, that's fine. So what?
I don't care about YOUR rules.

These are not MY rules, these were the general design
criteria so far, in order to make Celestia's display
SELFCONSISTENT. Surely, I have no problem with
add-ons that contradict Celestia's selfconsistence.
I just don't install them.

I just wanted to know.

For general educational reasons, I think it would be
good to let people know that these rings are not visible
to naked eyes...

Bye Fridger

[Boux]

Well, I am reading this additional Saturn ring business here since a few days. Could someone give me some scientific background reference whether these weak blue and red and... rings are visible for the naked eye!?

I am quite sure they are NOT!

So far the rules of the game in Celestia are that we ignore wavelength filters and essentially concentrate on phenomena that are visible without special instruments...

Bye Fridger

Of course, they are not visible with the naked eye.
What is your problem?
This is an add-on.
You don't like it, that's fine. So what?
I don't care about YOUR rules.

These are not MY rules, these were the general design
criteria so far, in order to make Celestia's display
SELFCONSISTENT. Surely, I have no problem with
add-ons that contradict Celestia's selfconsistence.
I just don't install them.

I just wanted to know.

For general educational reasons, I think it would be
good to let people know that these rings are not visible
to naked eyes...
Bye Fridger

Instead of being aggressive and unhelpful, your post could have simply be positive and bring interesting comments about the fact that these rings are visible through very long exposure times of on-board instruments.
Then, I clearly stated that this is all about an add-on.
Now, I will ask you to leave my thread alone.

[fsgregs]

Boux:

I admire your efforts here and do strongly urge that you make available the high res, barely visible ring, and the brighter one for flat panel displays. Both the blue and red rings are fine.

Regarding the visibility of the rings to the eye, I had not known that they were not visible without a UV filter. That said, I think your high res version is so verryyyyyyyyy dim that it just might be visible to someone in space, without an atmosphere. From what I have read, there is the slightest blue/violet component to the outer ring that is present in the visible spectrum.

They look done, so I eagerly await your release of them.

Frank

[t00fri]

Instead of being aggressive and unhelpful, your post
could have simply be positive and bring interesting
comments about the fact that these rings are visible
through very long exposure times of on-board
instruments.
Then, I clearly stated that this is all about an add-on.
Now, I will ask you to leave my thread alone.

Sorry I don't think my question was in any way
agressive. I just noticed that information was lacking in
this thread that I considered important.

It will not contribute to anybody's understanding if it is
not stated clearly under what conditions these
additional faint rings are visible. See e.g. Frank's
comments above. I really cannot understand why you
reacted so "impulsively" ...

Of course I will leave your thread alone if you so prefer.

Bye Fridger

[Boux]

OK, the package is ready.
You can grab it there:
http://jmmi.club.fr/celestia/e-ring/e-g-pack.zip
Just unzip it into your extras directory.
There are 3 ring textures with varying levels of visibility so that one is able to pick a choice, by commenting out the textures which will not show up.
The ssc file is also the README for this addon, with in-line comments.
I want to be clear: this is an addon whose purpose is to "portrait" Saturn's "E" and "G" rings which are otherwise too dim to be seen with the naked eye.
There is a lot of available literature about them on the net.
Enjoy!

[Chuft-Captain]

Boux,

Nice addon, but I have encountered a problem.

I'm using:
* Celestia version 1.4.1.
* No dedicated graphics card (laptop computer with shared memory graphics )
* The bright texture in your package.

PROBLEM: The rings disappear at greater distance or wider FOV as follows:

Start Celestia, press 6 for Saturn, press G to goto.


Press END key 7 times to recede from Saturn - All good so far :


Press END key once more, e-g rings disappear :


OR, instead of distance...alter FOV
Again, Start Celestia, press 6 for Saturn, press G to goto, (as before)
then...

PRESS <period-key> 29 times - All good so far :


PRESS <period-key> once more - e-g rings disappear :



regards
CC

[Johaen]

Boux,

Nice addon, but I have encountered a problem...

The same thing happens on my PC. My stats are in my sig.

[Boux]

It was deliberate on my side so that the rings are visible only when close to Saturn.
Edit the ssc file and increase the diameter of the dummy body inside Saturn from 1000 to let's say 10000.
The rings should then be visible in all circumstances.

EDIT: I have updated the pack and added relevant comment to the body's diameter line in the ssc file

[Chuft-Captain]

that seems to have fixed it.

Thanks

[Malenfant]

I think the new rings could actually be visible to the naked eye in certain conditions (ie from behind Saturn, with the sun hidden - though the light reflected from the main rings would probably drown them out). I don't think the exposure on those images was that long, otherwise the main rings would be entirely overexposed, and they're not.

I see no reason whatsoever to stop developing this. Though I think you made the colours somewhat too vivid - if they are toned down somewhat then I think it'd look more realistic.

[chris]

I think the new rings could actually be visible to the naked eye in certain conditions (ie from behind Saturn, with the sun hidden - though the light reflected from the main rings would probably drown them out). I don't think the exposure on those images was that long, otherwise the main rings would be entirely overexposed, and they're not.

I see no reason whatsoever to stop developing this. Though I think you made the colours somewhat too vivid - if they are toned down somewhat then I think it'd look more realistic.

It would be fairly simple to create a more realistic photometric model for the rings of Saturn, although tuning it to precisely match how the rings scatter light would be tricky. My plan is at some point to model the rings with two populations of particles: one of larger, primarily backscattering particles and a second one of very fine forward scattering particles. A second ring texture would contain the densities of the two types of particles in the red and green channels. In the region of the E ring, the texture would have red=0 (no large backscattering particles) and green > 0 (some low density of forward scattering particles), so that the rings would only be visible at high phase angles.

--Chris

[Boux]

It would be fairly simple to create a more realistic photometric model for the rings of Saturn, although tuning it to precisely match how the rings scatter light would be tricky. My plan is at some point to model the rings with two populations of particles: one of larger, primarily backscattering particles and a second one of very fine forward scattering particles. A second ring texture would contain the densities of the two types of particles in the red and green channels. In the region of the E ring, the texture would have red=0 (no large backscattering particles) and green > 0 (some low density of forward scattering particles), so that the rings would only be visible at high phase angles.

--Chris

The words from the man
This has to be processed in the OGL rendering code.

I think the new rings could actually be visible to the naked eye in certain conditions (ie from behind Saturn, with the sun hidden - though the light reflected from the main rings would probably drown them out). I don't think the exposure on those images was that long, otherwise the main rings would be entirely overexposed, and they're not.

I see no reason whatsoever to stop developing this. Though I think you made the colours somewhat too vivid - if they are toned down somewhat then I think it'd look more realistic.
--Malenfant

Anybody can rework the texture(s) according to his/her liking.
There cannot be anything realistic here... I am not sure 'realistic' makes any sense in the context anyway.

[Boux]

Hi, all,
I have updated the outer rings pack add-on to Version 2.
Changelog:
- reworked and desaturated the textures to look closer to Cassini's picts
- two choices: bright and dim (default) versions
- updated the ssc file which is also the FM
Go grab it there:
http://jmmi.club.fr/celestia/e-ring/e-g-rings-pack-V2.zip

Photometric model and back-scattering code by Chris would be welcome

[fsgregs]

Boux:

Your prior add-on for the rings had included ring5.png, which was a barely visible texture representing the G ring. I liked it the most of the 3 choices you offered in version 1.

This latest October revision 2 only includes ring3.png and ring4.png. I have unzipped it but not yet installed it. Did you intend to remove ring5.png as a 3rd alternative for the rings?

Should we not use it?

Frank

[Boux]

Boux:

Your prior add-on for the rings had included ring5.png, which was a barely visible texture representing the G ring. I liked it the most of the 3 choices you offered in version 1.

This latest October revision 2 only includes ring3.png and ring4.png. I have unzipped it but not yet installed it. Did you intend to remove ring5.png as a 3rd alternative for the rings?

Should we not use it?

Frank

The rings in revision 2 are color optimized versions, mostly desaturated versions of previous ring3 and ring4 in two intensity flavours.
Those are the more realistic ones, if realistic makes any sense before Chris implements the back-scattering rendering for rings.
Personally, I use eg-ring4.png which is the dimmer version.

[fsgregs]

Boux:

Thanks for all your work on the rings. Here is a screenshot of your new rev 2 ring-4.png in use around Saturn on my system.



I have ambient light set at "none".

Would the "G" ring appear that visible if we visited Saturn in person? If so, ... great! If not, do you think it should be toned down just a bit more? I would try to do so myself, but I have still not figured out how to adjust the brightness of a png transparent texture. Whenever I try to do so and save it, it never seems to save as transparent.

Frank

[Chuft-Captain]

Very nice Boux.

[Boux]

Boux:

Thanks for all your work on the rings. Here is a screenshot of your new rev 2 ring-4.png in use around Saturn on my system.

I have ambient light set at "none".

Would the "G" ring appear that visible if we visited Saturn in person? If so, ... great! If not, do you think it should be toned down just a bit more? I would try to do so myself, but I have still not figured out how to adjust the brightness of a png transparent texture. Whenever I try to do so and save it, it never seems to save as transparent.

Frank

Iwill make another further toned down version.
I am adding this on my Celestia to-do list for next week-end
I will try to make is invisible with ambient light set to none so that it shows up only with medium or high setting.
And...
Thanks Captain!

[fsgregs]

Boux:

I will try to make is invisible with ambient light set to none so that it shows up only with medium or high setting

If possible, make it slightly visible at ambient set to "none". That is the setting I use at default, and it would be nice to just be able to detect "something" there.

Thanks

Frank

[Chuft-Captain]

I would suggest calibrating the barely visible version for flat-panel display as they seem to be less bright than CRT's. (I'm sure you know this already )