New version of Celesia

[ComputerHotline]

Hello
Where I can download the new version of Celestia (I have version 1.3.2) ?
And
Does a software making it possible to calculate the laws of kepler for a moon around a gas giant exist ?

[jdou]

Salut,

Pour la 1??re question:
Si tu jettes un coup d'oeil un peu plus haut sur ce forum dans "Sticky Celestia 1.4.0 prerelease FAQ" initi?© par Chris tu trouveras ton bonheur.
Apr??s avoir install?© la version Anglaise, si tu vas sur http://celestia.myftp.org tu trouveras une version Windows de la 1.4.0 pour Franciser celle-ci.
Pour la 2??me question :
Euh...

Jdou

[t00fri]

...
And
Does a software making it possible to calculate the laws of kepler for a moon around a gas giant exist ?

Celestia does it perfectly! Put your gas giant and its moon in orbit, by specifying the orbit data in an *.ssc file. Then Celestia does the rest, including a great display!

Bye Fridger

[Evil Dr Ganymede]

...
And
Does a software making it possible to calculate the laws of kepler for a moon around a gas giant exist ?

Celestia does it perfectly! Put your gas giant and its moon in orbit, by specifying the orbit data in an *.ssc file. Then Celestia does the rest, including a great display!

Bye Fridger

I think he's asking if he can just put a moon at a certain distance around a gas giant and have Celestia figure out the orbital period (or enter the orbital period and have Celestia figure out the orbital distance).

If so, then Celestia can't do this, because it does not incorporate the masses of objects. You'd need to calculate the orbital period or orbital distance separately and input them into the ssc file.

[t00fri]

...
And
Does a software making it possible to calculate the laws of kepler for a moon around a gas giant exist ?

Celestia does it perfectly! Put your gas giant and its moon in orbit, by specifying the orbit data in an *.ssc file. Then Celestia does the rest, including a great display!

Bye Fridger

I think he's asking if he can just put a moon at a certain distance around a gas giant and have Celestia figure out the orbital period (or enter the orbital period and have Celestia figure out the orbital distance).

If so, then Celestia can't do this, because it does not incorporate the masses of objects. You'd need to calculate the orbital period or orbital distance separately and input them into the ssc file.

You are probably right as to his intentions (he and I should perhaps better have communicated in French ) . But I don't see any problem with Celestia doing the required job. When you set up an elliptical orbit in an ssc file, Celestia wants the orbit period as input, which is however trivially related to the mass via Kepler's 3rd law.

Code: Select all

(m+M)P^2 = (4pi^2/G) R^3


with m <<M being the moon's small mass as compared to the star's mass M, P the orbital period, R the orbital distance and G=Newton's constant.

So using a simple pocket calculator besides Celestia, he can easily choose among his preferred input parameters: distance, (star) mass, period,...The /non-trivial/ part of Keplers equations is then solved
and displayed by Celestia.