SDK Question oapiGetGlobalPos

[mstram]

The doc for 7.40.1.1 OAPIFUNC void oapiGetGlobalPos (OBJHANDLE hObj, VECTOR3 pos)
says "Returns the position of an object in the global reference frame."

and :

Note:
The global reference frame is the heliocentric ecliptic system at
ecliptic and equinox of J2000. Units are meters.
`
So why is the following code not returning values (close to) 0.0, 0.0, 0.0 for the Sun ? : (since it's supposed to be a *heliocentric* system ?)

OBJHANDLE hSun = oapiGetGbodyByName("Sun");
oapiGetGlobalPos( hSun, &sunGpos );

I'm getting : for( MJD 51623.000010 Mar 20 2000 00:00:00) :

Sun X: -1.00134e+009 Y: 2.96241e+007 Z:-5.0059e+008

 

[martins]

Bit of a misnomer. For "helio" in this case read "solar system" rather than just "sun".

 

[mstram]

Bit of a misnomer. For "helio" in this case read "solar system" rather than just "sun".

So are you saying that oapiGetGlobalPos is NOT using
"the heliocentric ecliptic system at ecliptic and equinox of J2000.

On a (maybe somewhat related note ....or worthy of a thread on it's own) ....

What is the code in sun.dll doing to calculate the position of the sun ?

Does that dll / Orbiter (in general) use the concept of
"The Galactic Center" ?

https://en.wikipedia.org/wiki/Galactic_Center#Distance_to_the_Galactic_Center

 

[martins]

What is the code in sun.dll doing to calculate the position of the sun ?

It calculates the barycentric position of the sun, using the VSOP87 series expansion.

Does that dll / Orbiter (in general) use the concept of
"The Galactic Center" ?

No.