These stars: http://www.cornucopia3d.com/purchase.php?item_id=2859&from=New&page=20

look wrong to me.  The stars that are in the earth's atmosphere would not shine through the atmosphere.  Am I right on this?

I don't think absolute realism was the point of that video. Otherwise, the clouds would not be right either... and I am not sure what to do with the UFO :) Now assuming this is not Earth but some other planet with a thinner atmosphere, the stars would look alright (the description does say it is an 'alien planet'). They shine through the thim layer of atmosphere of Mars from what I can tell, so why not ?

• agiel - www.linfa.net

The reason I ask is because I am making a planet animation. The client does not like the way the stars shine through the atmosphere.  I am looking at various examples to get a better perspective of space scenes and trying to get other people's opinions.

Thank you

If you want to make a realistic atmosphere, I think the gradient would have to be a lot sharper, with a bright layer close to the surface and a sharp decline to dark blue or purple going out. I just looked at google for images of the upper atmosphere to see if the stars can be seen through. It looks like stars appear a lot more faded on real pictures, especially with the light from Earth taking most of the light balance in the image. You can hardly see stars at all on these pictures.

• agiel - www.linfa.net

Attached Link: http://liftoff.msfc.nasa.gov/Shuttle/STS-75/media/photo/sunset.jpg

Here is an example of real photo of the upper atmosphere.

• agiel - www.linfa.net

Attached Link: http://quarknet.fnal.gov/graphics/earth.jpg

And here is another nice example, with a good view of the cloud layer.

• agiel - www.linfa.net

Agiel, thank you.

Attached Link: http://earthobservatory.nasa.gov/Newsroom/BlueMarble/BlueMarble_monthlies.html

And an absolute reference if you are trying to map Earth in 3D. From the Blue Marble program at NASA, a series of images of Earth with color series (per month), elevation, and bathymetrie. Yo ucan even find the night map if you look around links regarding 'Blue Marble'.

• agiel - www.linfa.net

Amazing.  There are some great monthly choices to use.

I'm going to rework the entire scene starting over to see if I can do better.

Thanks again.

AgielThose Earth Observatory textures are super :) - I used them many months ago on my (totally non-realistic) animation:

To Boldly Import Video (.WMV)

I grabbed a couple of Hubble nebula shots that I applied to alpha planes to make the sky a bit more interesting too.

I seem to recall that Monsoon created some cool space backdrops a while back too - Can anyone remember the links?

Jim Coe has some super models (and generously free) inlcuding a great Earth .VOB at:

http://www.art-head-start.com/free-stuff.html

Kind regards

Very nice earth model ! thanks for sharing the link

• agiel - www.linfa.net

Wow, that is a good earth that Jim Coe has made. 

Thanks everyone.

Jim's render of earth is great, but the atmosphere glow may be too much...?

Hi All, just noticed this thread.
Besides the great NASA textures, i used a large 'coffee table' book of photos of the Earth from space as a reference. Think i got a pretty realstic look, according to that book.

Naturally the atmosphere glow depends on the position of the sun and camera. I set it pretty hot for use in a particular scene
http://www.renderosity.com/mod/gallery/index.php?image_id=1052856&member and i don't think i changed it for the render above (to show my free model).

I think the absence of stars in near-Earth photos is (as Agiel mentions) a matter of camera exposure (lack of dynamic range). The Earth, with it's huge white cloud masses, requires camera exposures that are insufficient to show the stars that should show up. Same for photos from the Moon. And spacewalking Astronauts in direct sun must use dark filters in front of their eyes, so they can't see stars either - when in sunlight.

An important point about the visibility of stars through our atmosphere is that it is the brightness of the Earth's atmosphere - caused by Rayleight Scattering (explained at length in my eBook)from O2 molecules (and other incidental things the size of visible light ray wavelengths) that blocks starlight, not the atmosphere itself.

Without that Rayleigh Scattering of the sun's light, the zenith sky seen by noon sunlight would be black! Think about it. Take away the sun's light (i.e. look up on a clear, moonless night) and the Earth's atmosphere is seen to actually be very transparent - you see many stars (pollution aside). The atmosphere does not change it's chemical composition much at night, so the only explanation is no sunlight exists to be Rayleigh Scattered and the Earth's atmosphere is actually quite transparent, not the glowing light blue we see from the daytime scattering. 

So, if we had a different chemical composition in the atmosphere, with no molecules near the visible wavelengths in size, and thus no Rayleigh Scattering, we would see stars during the day from the ground.

 

JC thanks for the explanation.

In the link you posted, the earth looks like the stars are shining through the middle of the earth where the ocean would be.  Do you see what I mean?

Yes, a few people have commented on that - those are city lights, which are quite visible from space. Look closely and you'll see the outline of Florida, etc. This is a layer of my model which is also from a NASA texture (i.e. an actual photo of the world's artificial lighting at night).

Check it out sometime - a very fascinating image!
Here's a link:
http://visibleearth.nasa.gov/view_rec.php?id=11793

Lots of cool stuff at the NASA and Hubble Space Telescope sites.

Thank you.  That is interesting. 

The client has aready complained about the stars in the image that I am making so lights being visible on earth would not fly over.  I am now rendering it out and compositing the image to have more control over such subtleties.

Your space work is exceptional and inspirational.  I appreciate it all.

Hi CobraEye,

I composed a texture containing all the information from the blue marble.

You might have a look for inspiration:

http://www.renderosity.com/mod/gallery/index.php?image_id=1172571

(The atmosphere and scaling of bumpmaps was timeconsuming. Now I have to figure out

a way to make the Lights of the cities tranparent as they are exposed to daylight...)

cheers, bounzer.

PS: here is the same picture after I used photoshop...   ;-)

http://www.cornucopia3d.com/galleries/displayimage.php?album=lastup&cat=0&pos=164&pid=6912

Wow, that looks fantastic.  I especially like the varying colors of blue in the ocean.

Excellent work Simon!