Moving the Moon

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Rocketman
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Moving the Moon

Post #1by Rocketman » 13.12.2006, 16:56

I'm not sure if this is the correct place to post this, but I would like to tighten the Moon's orbit, moving it closer to Earth. Is this a difficult thing to do?

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selden
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Post #2by selden » 13.12.2006, 19:06

A problem is that the Moon's orbit is in the ecliptic plane. Celestia v1.4.1 and earlier place moons' orbits relative to their planets' equatorial plane. V1.5.0 and later allow you to specify ecliptic.

Except for that, just comment out the CustomOrbit line and modify the EllipticalOrbit appropriately.
Selden

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Cham M
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Post #3by Cham » 13.12.2006, 20:09

Selden,

you are confusing me. I'm at my office right now, so I can't test Celestia about the moons orbits, but I need to know :

In some extrasolar system, I define a moon "M" around a given planet "P". What is the moon's orbital plane by default ? If I set "Inclination 0" in its SSC code, is M's orbital plane parallel to P's equator, or parallel to Earth's Ecliptic (that would be insane!) ??
"Well! I've often seen a cat without a grin", thought Alice; "but a grin without a cat! It's the most curious thing I ever saw in all my life!"

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Rocketman
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Post #4by Rocketman » 13.12.2006, 23:38

selden wrote:A problem is that the Moon's orbit is in the ecliptic plane. Celestia v1.4.1 and earlier place moons' orbits relative to their planets' equatorial plane. V1.5.0 and later allow you to specify ecliptic.

Except for that, just comment out the CustomOrbit line and modify the EllipticalOrbit appropriately.


Thanks!

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Post #5by chris » 13.12.2006, 23:55

Cham wrote:Selden,

you are confusing me. I'm at my office right now, so I can't test Celestia about the moons orbits, but I need to know :

In some extrasolar system, I define a moon "M" around a given planet "P". What is the moon's orbital plane by default ? If I set "Inclination 0" in its SSC code, is M's orbital plane parallel to P's equator, or parallel to Earth's Ecliptic (that would be insane!) ??


In all versions of Celestia, the default orbital plane of a moon is the the equatorial plane of the planet it orbits. But, in Celestia 1.5.0 it's possible to use a different reference plane by defining an OrbitFrame.

--Chris

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Cham M
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Post #6by Cham » 14.12.2006, 00:08

Thanks Chris.
"Well! I've often seen a cat without a grin", thought Alice; "but a grin without a cat! It's the most curious thing I ever saw in all my life!"


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