Chapter 2: Motions of the Stars: Part II This tutorial is in two parts: Part IIa Part IIb Part IIaPlanetarium software: Stellarium (stellarium.org); GNU General Public License v3 (www.gnu.org/licenses/gpl-3.0.html) Part IIbPlanetarium software: Stellarium (stellarium.org); GNU General Public License v3 (www.gnu.org/licenses/gpl-3.0.html)