Who is really good with Celestia orbital parameters?

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Langrenus
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Langrenus
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With us: 5 years 8 months

#1by Langrenus » 23.11.2011, 16:29

Who is really good with Celestia orbital parameters?

I borrowed this lunar orbit and modified the Dates, Period, SemiMajorAxis, and Eccentricity, as well as reversing the orbital direction (hence, the minus sign) to that of an Apollo spacecraft lunar orbit. The modifications worked extremely well, except my orbital position (at any given time) is 28 degrees east (on the lunar globe) of where I want it to be. Is there any way (there surely must be) to shift my orbit 28 degrees to the west?

My Orbital Parameters


# Beginning 2440543.899510 # 1969 Nov 18 09:35:18
# Ending 2440544.677801 # 1969 Nov 19 04:16:02

EllipticalOrbit
{
Period -0.082878252656410776726
SemiMajorAxis 1843.1931 Eccentricity 0.0059492
Inclination 5
}

UniformRotation
{
Period 20
Inclination -30
}

Thank you, in advance, for your helpful input.

selden
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selden
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With us: 14 years 10 months
Location: NY, USA

Re: Who is really good with Celestia orbital parameters?

#2by selden » 23.11.2011, 21:23

You can use either MeanAnomaly or MeanLongitude in EllipticalOrbit to specify where the spacecraft was in its orbit relative to the perilune (i.e. relative to where it was closest to the Moon) on Jan. 1, 2000. By default, if they aren't specified, they have a value of 0.0 on Jan. 1, 2000; i.e. the spacecraft was at perilune on January 1st, 2000.

Alternatively, you can specify the Epoch when your orbital elements were correct -- i.e. the actual date when the spacecraft was at perilune.

SSC parameters are described at http://en.wikibooks.org/wiki/Celestia/SSC_File
Selden


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