Complex sentence: The first major claim of another moon of Earth was made by French astronomer Frédéric Petit, director of the observatory at Toulouse Observatory, France, who announced that he had discovered a second moon in an elliptical orbit around the Earth.
Split into simpler sentences: The first major claim of another moon of Earth was made by French astronomer Frédéric Petit, director of the observatory at Toulouse Observatory, France. Petit announced that he had discovered a second moon in an elliptical orbit around the Earth.