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Stellar atmosphres

Posted: 02.06.2007, 16:44
by Hungry4info
It seems to me that future versions of Celestia will not include atmospheres for stars. It's why I'm still sitting at 1.5.0pre1 lol.

I like the star effects for 1.5.0pre3, but still no atmospheres, and I don't expect atmospheres for stars to be in 1.5.0 final (a trend, so it's predictable, lol).

I would like to know how I can adjust celestia on my computer to show atmospheres around stars. Anybody have any tips?

Re: Stellar atmosphres

Posted: 02.06.2007, 17:06
by t00fri
Hungry4info wrote:It seems to me that future versions of Celestia will not include atmospheres for stars. It's why I'm still sitting at 1.5.0pre1 lol.

I like the star effects for 1.5.0pre3, but still no atmospheres, and I don't expect atmospheres for stars to be in 1.5.0 final (a trend, so it's predictable, lol).

I would like to know how I can adjust celestia on my computer to show atmospheres around stars. Anybody have any tips?



Easy ;-)...fog your monitor screen.

Bye Fridger

Re: Stellar atmosphres

Posted: 03.06.2007, 04:24
by Hungry4info
t00fri wrote:Easy ;-)...fog your monitor screen.


Yeah, that's about as much help as I expected. :(

Posted: 03.06.2007, 09:11
by cartrite
It can be done. It has been done, I think. I'm not sure how it's done as far as the details go. But it has something to do with defining a planet with a large atmosphere and have it orbit inside the star. With the new atmosphere code it may be possible to produce some strange effects too.

cartrite

Posted: 03.06.2007, 19:44
by Hungry4info
cartrite, I thank you for giving a sincere attempt to help. I'm trying to get the stars themselves to have atmospheres, I do not want to put planets in all 2 million stars in my version of Celestia lol.

Posted: 03.06.2007, 19:57
by cartrite
2 million. 8O That would be a little too much. I thought you were only doing 1 or 2.

cartrite

Posted: 03.06.2007, 20:01
by t00fri
Hungry4info wrote:cartrite, I thank you for giving a sincere attempt to help. I'm trying to get the stars themselves to have atmospheres, I do not want to put planets in all 2 million stars in my version of Celestia lol.


I already had written a post with the identical proposal that cartrite made. But I deleted it again, since I assumed you wanted ALL stars to have atmospheres. Therefore, at this time, there only remains to fog the monitor ;-) . Sorry...

Bye Fridger

Posted: 03.06.2007, 20:33
by Hungry4info
Alright, then why cannot the next version of Celestia be changed to where stars look nicer? It can be done, it's been done before, a long time ago, Stars looked very nice.

In my opinion, v1.4.1 was the apex of stellar renderings. But it seems to have gone downhill after that.

Image

Posted: 03.06.2007, 20:49
by t00fri
Well the reason for Chris returning for now to a clean "status quo" situation with little halo fraction (<=> "atmospheres") is due to the many negative comments that came from a number of us during the 1.5.0prex testing phases.

The big question is how to assume the relative growth of star disc versus halo size when the brightness increases. Since monitors have such a low dynamic range, halos are at hand for creating an impression of brightness. On the other hand, big halos also create physical "nonsense" as was widely discussed elsewhere in the forum.

If you need pointers to the physical nonsense, let me know ;-)

So altogether you can be assured that neither Chris nor anyone of us decided easily to return for now to a rendering with comparably little halo fraction.

Bye Fridger

Posted: 03.06.2007, 21:59
by julesstoop
Still, I think no 1.4-style halo but a much thinner atmosphere-like layer to soften the edges of the disk a little would look better.

Posted: 03.06.2007, 22:09
by Kolano
t00fri wrote:Well the reason for Chris returning for now to a clean "status quo" situation with little halo fraction (<=> "atmospheres") is due to the many negative comments that came from a number of us during the 1.5.0prex testing phases.


I thought most of the complaints were actually in regard to the planets/moons picking up large glowing halos not the stars?

Posted: 03.06.2007, 22:10
by t00fri
julesstoop wrote:Still, I think no 1.4-style halo but a much thinner atmosphere-like layer to soften the edges of the disk a little would look better.


I agree and actually have proposed that to Chris: letting the halo grow up to 25% of the disk size. Chris was apparently quite frustrated at this point and almost totally reset the halo.

Bye Fridger

Posted: 03.06.2007, 22:17
by t00fri
Kolano wrote:
t00fri wrote:Well the reason for Chris returning for now to a clean "status quo" situation with little halo fraction (<=> "atmospheres") is due to the many negative comments that came from a number of us during the 1.5.0prex testing phases.

I thought most of the complaints were actually in regard to the planets/moons picking up large glowing halos not the stars?


Stars, too. In case of the stars the main issue was Chris' originally LARGE halo.

Image

Here is my example from
http://www.celestiaproject.net/forum/viewtopic ... sc&start=8

There is oviously substantial physical nonsense at display, related to the enhancement of background stars behind the halo! See my respective discussion in that thread. This is presently hard to avoid if we want large halos.

Bye Fridger

Posted: 12.06.2007, 22:31
by fsgregs
In my educational activities, the inner glowing halo of a star is an ideal representation of the chromosphere of a star, and the outer halo is a great corona representation. My students recognize them instantly. Halos and star atmospheres are NEEDED in Celestia. I have not yet downloaded 1.5 onto my system, because it inactivates several of the great add-ons that Runar and others have created for 1.4.1 and earlier. If it wipes out star halos and atmospheres as the screenshots indicate, I would plead with Chris to add halos back. :cry:

Please!!!!! :? :? :? :?

Perhaps it can be a cfg option. Turn star halos on ... or off. Let the user decide.

Frank

Posted: 12.06.2007, 22:50
by Cham
I agree. The star rendering (without atmosphere) is lame. It's a major downgrade here. :cry:

Posted: 13.06.2007, 07:39
by bdm
fsgregs wrote:Perhaps it can be a cfg option. Turn star halos on ... or off. Let the user decide.

This is a very good idea, as everyone can then have the halos that they want. Perhaps these options should be more than just on/off options. Being able to configure the the size of the halos would be useful.

My personal taste - configure an inner halo that is just big enough to hide the jaggy edges of the star, and an outer halo that looks like a corona.

Posted: 13.06.2007, 07:41
by Cham
The stars need AT THE VERY LEAST a thin atmosphere like what we had in Celestia 1.4.

Posted: 13.06.2007, 09:49
by t00fri
Cham wrote:The stars need AT THE VERY LEAST a thin atmosphere like what we had in Celestia 1.4.


You know about the corresponding VERY unphysical enhancement of background stars by star halos. This really "hurts" ;-) . Apart from this nasty effect, everybody would be in favor of star atmospheres, of course.

Bye Fridger

Posted: 13.06.2007, 20:28
by Hungry4info
Yes, that is a problem. I say let's fix it.
You can see stars through the atmosphere of the planets in Celestia (provided, of coruse, you're not in the atmosphere). I've always thought they would not be visible. Is it possible to have it to where when seeing stars through an atmosphere, they're significantly dimmed?

Posted: 14.06.2007, 03:01
by Don. Edwards
This is precisely why I am not moving forward on any new builds past 1.5 pre2 until this problem is solved.

I always thought if something?€™s works well than leave it alone. Chris tried to upgrade things, but it turned out to bring in other major problems, mainly moons looking like little stars, which I hate, so until he can solve the problem for a future build he should put things back the way they were if at all possible. At this point I am willing to live with the halo effect on the moons, for now, but I will not do any further upgrades until this is fixed to everyone?€™s satisfaction.

It?€™s also a shame that so many add-ons seem to be impacted negatively with the code changes at this point. These newer builds are starting to feel like a totally different and new version of Celestia, with a very different look and feel. I even noticed recently that the time settings has been changed so that there no longer has a small box pop up to advance the time by months in a quick click. Now you have to highlight the section of the date you want and advance it with the arrow keys. I liked the old way better although it did look tacked on sort of.

Oh well we will just have to wait and see.

Don. Edwards