Binary star system screen shots

[kikinho]

Chris, this new feature will be part of Celestia 1.3.3?

[chris]

Chris, this new feature will be part of Celestia 1.3.3?

It will be part of the next Celestia release, which will have a version number different than 1.3.3.

--Chris

[kikinho]

And the next version will have support for multiple star systems? Also, the new version will have support for greenhouse effects on planets in ssc files? It's because the temperatures on Venus and on Earth are wrong. For you have an idea, Venus temperature is 231K and Earth is 259K. It's wrong, right?

[Fafers]

Also, the new version will have support for greenhouse effects on planets in ssc files? It's because the temperatures on Venus and on Earth are wrong. For you have an idea, Venus temperature is 231K and Earth is 259K. It's wrong, right?

That would be a good idea. One could include a line in the ssc file like, for example, "Greenhouse 15" and Celestia would add 15 Kelvin to the "normal" temperature of the planet.

[kikinho]

Yes, I tottaly agree with this brilhant idea. I think that many people in this community like Dr. Evil Ganymede and others will like it.

[chris]

And the next version will have support for multiple star systems? Also, the new version will have support for greenhouse effects on planets in ssc files? It's because the temperatures on Venus and on Earth are wrong. For you have an idea, Venus temperature is 231K and Earth is 259K. It's wrong, right?

The next version will have support for multiple star systems--not much point in having multiple light sources without multiple suns, right?

I have no intention of adding a greenhouse parameter.

--Chris

[chris]

Here are a couple shots of a bump mapped planet illuminated by two suns:





The bump effect is fairly subtle without greatly exaggerated surface relief. The still images don't quite capture the effect; it's much more fascinating to watch the planet rotate in accelerated time and move through odd two sun phases.

This screenshot was taken with the new OpenGL 2.0 render path I've been working on. This render path requires a recent graphics card (GeForce FX/Radeon 9500 or later), is the highest quality, and will feature certain effects unavailable in other render paths. In OpenGL 2.0 mode, Celestia builds high-level OpenGL shading language programs at run time instead of using special hand-written shaders in external files. The benefit is that new lighting models and render settings can be introduced without having to create a whole new set of shader files. My first effort along these lines will probably be replacing the Lambertian with Lommel-Seeliger reflection.

--Chris

[Evil Dr Ganymede]

My first effort along these lines will probably be replacing the Lambertian with Lommel-Seeliger reflection.

Cha-CHING!

Now we're talking!

[kikinho]

Could the planet be also illuminated by a browndwarf?

[Rassilon]

Chris,

You probably should allow an edit in the ssc files for planetary temprature...Just a simple line say Temprature 100 for 100 Kelvin. This would give a more appropriate temprature for planets such as Venus...

Very nice bumpy mars there....I cant wait for the next release!

[selden]

kikinho,

If it's defined as a Star, it'll illuminate the planets in its system.

[Evil Dr Ganymede]

kikinho,

If it's defined as a Star, it'll illuminate the planets in its system.

And that's user-definable, yes? So you could theoretically define "Earth" as a Star and it'd light things up?


Brown Dwarfs are a bit odd anyway - they're bright enough to illuminate nearby objects when they're very young and still actually fusing something inside them, then they fade out rapidly over time when that stops.

[granthutchison]

kikinho,

If it's defined as a Star, it'll illuminate the planets in its system.

And that's user-definable, yes? So you could theoretically define "Earth" as a Star and it'd light things up?

It's user-definable to the extent that something defined in an stc file is a star ... you can't (at present, anyway) define stars in an ssc. So you could make yourself a star-like Earth by removing Earth from solarsys.ssc, and then defining a star with Earth's orbit around the Sun, Earth's surface texture, and Earth's rotational parameters.

Grant

[kikinho]

I'm doing a small cluster of stars that have at least 5 near stars. I'm thinking of putting more stars. The stars I've done are a pulsar in the middle, a K3V star, a M6V star near the K3V star, a F8V star, a G6V star and a L2VI star. One of the planets I made is in the G6V star. I will only finish the entire cluster when I can download the next version of Celestia. I think you sad that in the next version it will be able to a planet be illuminated by more than 2 stars. If it's true, I think that my planet will be multi-colored. In reality, the planet will be illuminated by more than 2 stars.

What do you think about this?

I think that Chris, Evil Dr. Ganymede and Rassilon will be interested in this idea. It's because this cluster will be my next addon. And in this cluster there are many stars with planets. The textures are good until now.

[Dollan]

Just out of curiosity, do you have any screenshots of various types of binaries (contact binaries, close orbiting ones, widely seperated ones, etc?)

Also, how will this new development effect stars that have been defined with stellar companions already, ala the nearstars data file?

Or, for that matter, will it be possible to add a true stellar companion to any star (thinking of my recent Gamma Leporis B add-on) rather than simply defining a nearby star?

...John...

[granthutchison]

Also, how will this new development effect stars that have been defined with stellar companions already, ala the nearstars data file?

The "emissive planets" stars will still appear as emissive planets, just as they did before. But I've already built a completely new Nearby Stars add-on with all the companions defined as stars. I'm not sure whether Chris will want to include this in the distribution in future, or whether it will continue as an add-on.

Or, for that matter, will it be possible to add a true stellar companion to any star (thinking of my recent Gamma Leporis B add-on) rather than simply defining a nearby star?

Yes, you can do this easily. In fact, you can over-ride the distribution version of Gamma Leporis A and replace it with a star in a barycentric orbit with your added B.

Grant

[Dollan]

The "emissive planets" stars will still appear as emissive planets, just as they did before. But I've already built a completely new Nearby Stars add-on with all the companions defined as stars. I'm not sure whether Chris will want to include this in the distribution in future, or whether it will continue as an add-on.

Ooo. Certainly look forward to that one, regardless of how it's redistributed.

...John...

[Evil Dr Ganymede]

Yes, you can do this easily. In fact, you can over-ride the distribution version of Gamma Leporis A and replace it with a star in a barycentric orbit with your added B.

How does that work when you have more than one star defined in the stars.dat file in a multiple system? IIRC there are a few systems in Celestia where a star within a lightyear of another is predefined too.

[granthutchison]

Yes, you can do this easily. In fact, you can over-ride the distribution version of Gamma Leporis A and replace it with a star in a barycentric orbit with your added B.

How does that work when you have more than one star defined in the stars.dat file in a multiple system? IIRC there are a few systems in Celestia where a star within a lightyear of another is predefined too.

You just over-ride the B component, too. Here's the Alpha Cen pair from my new add-on, as binary orbits are currently implemented:

Code: Select all

71683 # ALF Cen A
{
   RA 219.916998
   Dec -60.83748372
   Distance 4.395
   SpectralType "G2V"
   AppMag 0.01

   EllipticalOrbit {
      Period          79.914
      SemiMajorAxis   10.8928   # mass ratio 1.09:0.92
      Eccentricity    0.5179
      Inclination   82.98
      AscendingNode   67.71
      ArgOfPericenter 3.77
      MeanAnomaly     200.12
   }
}

71681 # ALF cen B
{
   RA 219.916998
   Dec -60.83748372
   Distance 4.395
   SpectralType "K0V"
   AppMag 1.34

   EllipticalOrbit {
      Period          79.914
      SemiMajorAxis   12.7872   # mass ratio 1.09:0.92
      Eccentricity    0.5179
      Inclination   82.98
      AscendingNode   67.71
      ArgOfPericenter 183.77
      MeanAnomaly     200.12
   }
}

Celestia notes the Hip numbers in the stc, and over-rides the corresponding stars.dat entries.

Grant

[Evil Dr Ganymede]

Why do you need to define the RA and Dec for the companion? Isn't that a bit redundant, if Celestia already knows it should be orbiting the A star (or the barycentre, if applicable)? i.e. why not just define the RA/Dec for the barycentre of the system and leave it out of the definition of the stars?