There should be a preview of the planets in galacticraft and what better way to do that then using the LookingGlass API to render planets.
the download link for the api :
http://minecraft.curseforge.com/mc-mods/230541-lookingglass/files/2240827
the download link for the api :
http://minecraft.curseforge.com/mc-mods/230541-lookingglass/files/2240827