Celestia Forums

Here's a preview of some more work that I've been doing on atmospheres. I'm pretty happy with the way the moon looks in a daylit sky now:



And here it is again with a little bit of ambient light added to simulate earthshine:



The bluish cast is a bit too strong--that should be fixed somewhat when I adjust the sky color. In any case, it's much better than dark shadowed sphere from 1.3.0.

Eventually, I may try and automatically add Earthshine (or Jupitershine or whatever) for satellites . . . This would be especially noticeable on artificial satellites in low Earth orbit. Is this something that's interesting to anyone?

--Chris

Hey Chris,
Are you still going to try and implement moonshine? Ah I mean the light that is reflected from a moon on it's planet on the darkside. An example is full moon lighing the darkside of Earth.

Don.

Very nice work indeed! I'm eager to see the result on artificial satellites!
Is this also going to improve the eclipse's rendering ? (I mean the reddish colour of the eclipsed moon)

is that the real moon?!? (hehehe )

Chris you really are working hard to make a 100% perfect Solarsystem simulator

Impressive . Very Very beautiful.

Bye - Paolo

Calculus,
As far as I understand this effect as nothing to do with the colored shadow in eclipse that is due to wavelenght selective light scattering by the atmosphere of the occulting body, This is just to "simulate" (I use the same wording as that used by Chris). Same thing, for the "real" earth shine. Incidently if you want the colored moon eclipse viit the Gordon site and download a celestia version (exe) that simulate this effect . See previous trheads. Just replace the present exe by this one. It is a minor change and you should not get any problem. This effect can easily be extended to the shadow generated by any occulting body having an atmosphere. But the code has to be slightly modified. and then for each "planet with atmosphere" RGB color should be indicated in the data sheet. Simple indeed, except for the choice of color! However knowing the atmosphere composition, perhaps a "good" physicist can evaluate the colors .
MB

MB wrote:However knowing the atmosphere composition, perhaps a "good" physicist can evaluate the colors.

It'll be a shade of red more or less every time. The fact that atmospheres scatter blue wavelengths is independent of the molecules they're composed of.

Grant

granthutchison wrote:

MB wrote:However knowing the atmosphere composition, perhaps a "good" physicist can evaluate the colors.

It'll be a shade of red more or less every time. The fact that atmospheres scatter blue wavelengths is independent of the molecules they're composed of.

That's true, but only within limits. If the dominant process is Rayleigh dipole scattering then blue light will be preferentially scattered and red light transmitted. However, if the scattering is dominated by larger particles (as on Mars, or in that sandstorm that happened during the war in Iraq) then the scattered light might be some other color. And there are other processes that scatter the whole visible spectrum pretty much uniformly, such as what happens in white clouds. It's also possible that a resonant process of some sort could emphasize certain wavelengths in a gas.

Matt McIrvin wrote:That's true, but only within limits.

Which was why I said "more or less every time"

But the trouble with particulates is:
1) They need a gaseous atmosphere to keep them aloft, so there's always a background of Rayleigh scattering - no amount of green dust will look green if it is seen in red sunset light.
2) They are pretty absorptive, so often they serve only as a barrier to light transmission - like clouds on the Earth's limb darkening the redness of lunar eclipse light.

Grant