Johannes Kepler didn't immediately figure out that planets move in elliptical orbits. He actually went through a process of observation, analysis, and refinement of his ideas.

Here's a breakdown of the key events:

* 1609: Kepler published his first two laws of planetary motion, which stated:

* First Law: Planets orbit the sun in elliptical paths with the sun at one focus.

* Second Law: A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.

* 1619: Kepler published his third law of planetary motion, which relates the orbital period of a planet to its average distance from the sun.

So, while Kepler's work on elliptical orbits began in 1609, his full understanding of the laws of planetary motion and the elliptical shape of planetary orbits wasn't solidified until 1619.