This script allows full user experimentation from within Celestia of the different frames, coordinates and orientation available.
It is a complement to the now finished
documentation on that subject available on the site :http://ralph.buisson.9online.fr
It permits the user a 'subjective' undestanding (from a user's point of view) of all the 'objective' definitions and aspects described in the other pages of this site.
With this script, a complete experimentation is possible, regarding:
- each Celestia Frame
- each associated Axis and Origin
- each Coordinates sytem ( both rectangular and spherical) related to the observer position in space
- the Orientation system associated with the camera of the observer
For Lua-Celx programmers:
This script is documented to give some hints and first answers to anyone intending to start programming :
- the observer positionning in space, using the different frames of Celestia
- the camera orientation in space, using the quaternion/orientation technology of Celestia
This script, written in Lua celx, is strongly interactive and thus needs a recent version of Celestia (including the celestia_keyboard_callback implementation): Celestia version v.1.3.2 pre7 or higher is fine for this purpose.
Please report any error
and/or question 
on this forum where my username is 'rjp buisson'
Enjoy...
Jean Pierre
http://ralph.buisson.9online.fr