In 1600 Johannes Kepler becomes an assistant to Tycho Brahe. In 1609 Kepler publishes his first two laws of planetary motion. Kepler's first law is based on a calculation of an elliptical orbit for Mars using Brahe's data. He publishes his third law in 1619.

Galileo first observes Mars in 1609 with his primitive telescope.

Dutch astronomer Christiaan Huygens makes the first sketch of Mars in October of 1659. He calculates the rotational period of Mars to be 24 hours. In 1672 Huygens observes the southern polar cap. Cosmotheoros is published in 1698 by Huygens, in which he speculates on extraterrestials.

During the Martian opposition of 1666 Giovanni Cassini draws Mars and determines a day length of 24h 40m.