Spkpos is an important Blueprint action. It computes the position of one ephemeris body with respect to another.
Spkpos
Abstract
Return the position of a target body relative to an observing body, optionally corrected for light time (planetary aberration) and stellar aberration.
The position of Moon with respect to the Earth/Moon Barycenter
Inputs
| Input | Value |
|---|---|
et |
Ephemeris Time: now |
Targ |
Target: MOON |
Obs |
Observer: EARTH BARYCENTER |
Ref |
Reference Frame: IAU_EARTH |
Abcorr |
Aberration Correction: None |
Outputs
| Output | Value |
|---|---|
Ptarg |
Position as SDistance Vector |
Lt |
Light travel time |
We can use the result, Ptarg to place celestial bodies in a solar system simulation for a given et value.
