I have a problem with celestia

[Malenfant]

I'm not "replacing" it, per se. I never edited ANYTHING out of the RL star. I simply put a fake star in orbit around the RL star.

Yes, but that's my point . I don't think you CAN see illumination from other stars in a binary system UNLESS you have them orbiting a barycenter. IIRC Just having a star object with emissive true doesn't create a new light source, it just makes an object that glows when looked at but doesn't actually provide light.

But if you have two stars orbiting a barycentre defined in the stc, then the ssc knows that there are two lightsources to illuminate the planet with. That may be why your planet isn't being lit by both stars.

[PlutonianEmpire]

I'm not "replacing" it, per se. I never edited ANYTHING out of the RL star. I simply put a fake star in orbit around the RL star.

Yes, but that's my point . I don't think you CAN see illumination from other stars in a binary system UNLESS you have them orbiting a barycenter. IIRC Just having a star object with emissive true doesn't create a new light source, it just makes an object that glows when looked at but doesn't actually provide light.

But if you have two stars orbiting a barycentre defined in the stc, then the ssc knows that there are two lightsources to illuminate the planet with. That may be why your planet isn't being lit by both stars.

Look at the first pic I posted. then, turn off EVERY SINGLE LIGHT IN THE ROOM. If it's daylight outside, shut the shades. THEN perhaps you should see a FAINT light.

Trust me, I saw it myself.

if that doesn't work, try it again, but on a laptop.

Still can't see the dimmer star's light?

here's the same image, but with brightness enhanced:

[Malenfant]

Well, I used your planet code around the barycentered version of the system I made, and there IS something odd going on.

I used this code since I don't have your textures.

Code: Select all

"Volcanica" "HIP 85569 B" {
   Texture "earth.*"
   Radius 5610.000
   Oblateness  0.180
   Color [ 0.14 0.72 0.19 ]
   BlendTexture true

   Atmosphere {
      Height 56.100
      Lower [ 0.36 0.14 0.04 ]
      Upper [ 0.20 0.41 0.52 ]
      Sky [ 0.29 0.28 0.71 ]
      CloudHeight  5.610
      CloudSpeed  10.000
      CloudMap "earth-clouds.*"
   }

   EllipticalOrbit {
      Period            0.6758
      SemiMajorAxis     0.018283870967741935483870967741935
      Eccentricity      0.0000
      Inclination       0.0000
      MeanAnomaly       168.3022
   }

   Obliquity                0.000

   Albedo           0.16
}


The weird thing is that it's illuminated by the blue giant, but isn't illuminated by the M star (though when the planet is lit by the giant, it looks murky and green - I think that's down to your atmosphere settings though). I had it set up so that the M is on one side and the blue star is on the other and all I saw was the illumination from the blue star.

ISTR when I was testing it when it first was implemented that Celestia interally scales the illumination when it's doing the multiple light sources, it could be that the illumination from the blue star is swamping the red star so much that it's just not showing the illumination from the latter.

In fact, I just tested it now by changing the AbsMag for the blue giant to +6.5, which makes it comparable to the M star. When I view the planet again with the M star on one side and the 'blue star (now shrunken considerably)' on the other, I CAN now see the illumination from that - it's dim though, because it's now 4 magitudes less bright than the red star.

If you set the AbsMag of the blue star to be +2.5, you'll get both stars at pretty much equal brightness when they're on opposite sides of the planet - now you'll see both sides equally illuminated. So basically, it all depends on the relative magnitudes of the stars as seen from the planet - if they're about the similar (within about 1-4 magnitudes of eachother) then you'll see some illumination from the other star. If they're much more different than that then you won't see the illumination from the dimmer star because Celestia just doesn't bother rendering that. IIRC it had something to do with simulating what the eye would actually see.

So I'm pretty certain that the illumination isn't seen from both stars in your system because the blue star is so much brighter than the red one.

[PlutonianEmpire]

Getting rid of the "blendtexture true" might also help.

Personally, i think that Celestia's illumination models are currently unrealistic. for example, when you go straight from mercury to pluto, you'll notice that both planets are lit EXACTLY the same as each other, when in reality, pluto should appear much darker, due to its distance from the sun.

[Malenfant]

Personally, i think that Celestia's illumination models are currently unrealistic. for example, when you go straight from mercury to pluto, you'll notice that both planets are lit EXACTLY the same as each other, when in reality, pluto should appear much darker, due to its distance from the sun.

Yes, but that's a known issue. If it was rendered realistically then you wouldn't see anything at Pluto. I think it's a hardware limitation - computer monitors don't have the same sort of range as the human eye, or something like that.

But yeah, the sun is about 1600 times less bright at Pluto than it is at Earth.

Though it does make me wonder why Celestia bothers with simulating the response to human eyes in a binary system if it doesn't bother to do it in a solo one...

[PlutonianEmpire]

Though it does make me wonder why Celestia bothers with simulating the response to human eyes in a binary system if it doesn't bother to do it in a solo one...

And THAT is my problem with celestia!

THE END

[Malenfant]

Well, before you say "The End", did that actually fix your problem? (or at least, did you realise that was why you couldn't see the illumination from both stars?)

[PlutonianEmpire]

I put in "the end" as a joke

[ajtribick]

You seem to not have noticed my edit in the previous post:

Set up this system myself (required editing of starnames.dat, apparently 1.4.0pre6 doesn't recognise catalogue references in the OrbitBarycenter field, perhaps I should upgrade), the red dwarf is at apparent magnitude -29.74, the blue star is a magnitude -38.08, which means that the blue star appears to be over 2000 times brighter.

Not surprising that the red dwarf isn't providing much illumination.

[Malenfant]

You seem to not have noticed my edit in the previous post:

Set up this system myself (required editing of starnames.dat, apparently 1.4.0pre6 doesn't recognise catalogue references in the OrbitBarycenter field, perhaps I should upgrade), the red dwarf is at apparent magnitude -29.74, the blue star is a magnitude -38.08, which means that the blue star appears to be over 2000 times brighter.

Not surprising that the red dwarf isn't providing much illumination.

I didn't notice it actually, that's what got me wanting to write the proper barycenter code and test it out myself...

Could you set the system up in such a way (eg by tweaking the AbsMags, like I did) to get any illumination from the other star on the planet? I'm assuming you're using PE's original code, not the dedicated barycenter code that I wrote? My understanding is that my code is actually the correct way to get multiple star illumination to work.

[ajtribick]

Put the red dwarf in orbit around Gamma Virginis (note that I am NOT using t00fri's binary stars catalogue - I'm being a bit slow on the upgrade):

Code: Select all

"Vulcana" {
   SpectralType "M3V"
   AbsMag 10.500

   OrbitBarycenter "GAM Vir"

   EllipticalOrbit {
      Period             0.2085
      SemiMajorAxis      1.000
      Eccentricity       0.000
      Inclination        0.000
      AscendingNode      0.000
      ArgOfPericenter    0.000
      LongitudeNode      0.000
   }
}

I see noticeable illumination from both stars.

[PlutonianEmpire]

You seem to not have noticed my edit in the previous post:

Set up this system myself (required editing of starnames.dat, apparently 1.4.0pre6 doesn't recognise catalogue references in the OrbitBarycenter field, perhaps I should upgrade), the red dwarf is at apparent magnitude -29.74, the blue star is a magnitude -38.08, which means that the blue star appears to be over 2000 times brighter.

Not surprising that the red dwarf isn't providing much illumination.

I never did look at the B star for the appmag. silly me. *bashes head against wall*