Space Engine - Solar/Lunar Eclipses

AnimsSpace · 23 Dec 2016 09:16

Here I would like to talk about Eclipses and Transits in Space Engine.

23 Dec 2016 10:12

I would have put this thread under "General Discussions" instead of off-topic, but I think the eclipses and transits could be improved especially in the Solar System. For some reason the solar eclipses on Earth don't work very well

AnimsSpace · 23 Dec 2016 11:50

I would have put this thread under "General Discussions" instead of off-topic, but I think the eclipses and transits could be improved especially in the Solar System. For some reason the solar eclipses on Earth don't work very well

Ok, i do it.

23 Dec 2016 11:53

AnimsSpace, let a mod handle it, they can move threads around. Don't make a new thread.

23 Dec 2016 11:53

guess I was too late

AnimsSpace · 23 Dec 2016 11:55

can i delete a Thread?

23 Dec 2016 11:56

I think so. Just go to that first post of the new thread you just made and there should be an "X" in a box where the ", edit, and report buttons are.

AnimsSpace · 23 Dec 2016 11:58

Ok, do you have Seen A Solar/Lunar eclipse in Real Life?

23 Dec 2016 12:03

I have seen several lunar eclipses, but not a Solar eclipse. I think nearly everyone in this forum who lives in America is excited for this Solar eclipse

Julian · 23 Dec 2016 19:51

I'm disappointed that lunar eclipses in Space Engine don't turn the Moon red, which is a feature Celestia has. For that matter, any time you look at the Earth with the Sun behind it in SE, the atmosphere looks like a white ring instead of a red one, which seems to be a limitation of the atmosphere model.

YouTube · 23 Dec 2016 21:18

any time you look at the Earth with the Sun behind it in SE, the atmosphere looks like a white ring instead of a red one

Certainly not white

Compare with reality

They're quite similar.

What you need in order to accurately simulate the coloration of an eclipse for a given world is to 1) know what its sunset color is (which I don't know how easy it is to calculate with this atmosphere model), and 2) simulate atmospheric refraction (which SE currently doesn't do). You could "fake" it for catalog worlds, by manually inserting some parameters, but this would be a lot of work for an effect that would only be visible in one star system.

23 Dec 2016 21:29

Julian, if you mean something like this, I can't seem to find information about exposure or instruments used to take those images, but usually they're a bit overexposed, plus light pollution takes part of the merit and glacial albedo too. Surely atmosphere models in SE can/will be tweaked and perfected.
For what is worth, SE right now doesn't even try to emulate solar and lunar eclipses, for the algorithms used for solar system calculations doesn't use yet a VSOP87 model but a simpler keplerian simulation.
Still, some visuals are impressive sometimes.

Julian · 24 Dec 2016 15:28

I meant that this is what Earth looks like from the Moon during a lunar eclipse in Space Engine. The atmosphere isn't red, and it doesn't illuminate the Moon.

YouTube · 24 Dec 2016 21:09

I meant that this is what Earth looks like from the Moon during a lunar eclipse in Space Engine.

Zoom in on the atmosphere, it's not white, it's a mixture of colors, as it should be.

The atmosphere isn't red, and it doesn't illuminate the Moon.

The Moon doesn't turn red because Earth's atmosphere is red, it turns red because sunlight passes through the atmosphere, loses its short wavelength colors in the process, and is refracted into Earth's shadow. It's actual direct sunlight that makes the Moon red during an eclipse, not the atmosphere being red. And since SE doesn't simulate atmospheric refraction at present, it can't show this.

See this actual picture taken from Earth's shadow:

Notice that the atmosphere isn't red at all, and also isn't very bright. It's sunlight that's red. Sunlight that's been diffracted into Earth's shadow where it wouldn't normally be visible.

24 Dec 2016 21:26

I've watched hundreds of sunsets in orbit. Like you can see in the picture in message 11, only the atmosphere closest to the planet appears red and when the sun is seen through that atmosphere it appears red.
This video is what it looks like in real time.
[youtube]tfwFer6T7Ko[/youtube]

And here's a picture I took myself

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