1609 After studying Tycho Brahe's observations of Mars' elliptical orbit, Johannes Kepler published his first two laws of planetary motion in Astronomia Nova (New Astronomy).

1609-11-30 The telescope, invented in Holland in 1608, was used for astronomy for the first time, by Galileo Galilei. Using it he discovered the four largest moons of Jupiter in January 1610.

1619 Kepler announced his 3rd Law of planetary motion.

1627 Kepler published his table of planetary motions, the Rudolphine Tables.

1636 Francesco Fontana produced a crude drawing of Mars based on telescopic observations.

1636-08-24 Fontana produced a second drawing of Mars.

1644-12-24 Two patches on the lower part of the disk of Mars were described by a Neapolitan Jesuit named Father Bartoli.

1659-11-28 Christiaan Huygens observed Mars with his homemade telescope, and sketched a V-shaped patch recognisable as Syrtis Major. A few days later, December 1, he noted "The rotation of Mars, like that of the Earth, seems to have a period of 24 hours."

1664 Giovanni Domenico Cassini detected patches on the surface of Mars. He eventually determined (independently from Huygens) a rotational period for Mars of 24 hours and 40 minutes.

1666-03 Robert Hooke of the Royal Society of London made primitive drawings of Mars showing Syrtis Major and other features.

1671 At the Paris Observatory, Cassini discovered Iapetus, a satellite of Saturn, with a 5.2m telescope. A year later, he discovered Rhea using a 10.4m telescope.

1672 Cassini worked out the parallax of Mars, which gave the distance from Earth to Mars.

1672-09 With Mars at opposition, Huygens made the first clear drawing of the southern polar cap.

1684 Cassini discovered Dione and Tethys, two more satellites of Saturn, with 30.4m and 41.5m telescopes.

1686 Bernard le Bovier de Fontenelle, in his Entretiens sur la pluralité des mondes (Conversations on the plurality of worlds), stated "Mars isn't worth the trouble of stopping there."

1687 Isaac Newton published Mathematica Principia.

1698 Huygens book Kosmotheoros is published 3 years after his death, in which he asserted that the planets must have vegetation and animals.

1719 After observing Mars at the perihelic oppositions of 1704 and 1719, Giacomo Filippo Maraldi confirmed his uncle's (Cassini) measurement of 24 hours and 40 minutes for Mars' rotational period. He also commenced the first thorough study of the Martian poles.

1777 William Herschel made his first observations of Mars using homemade reflectors. He recorded "two remarkable bright spots on Mars" (the polar caps).

1781-03-13 Herschel discovered Uranus with a 6.1m reflector. He thought it was a comet.

1781-07-27 Herschel calculated a rotational period for Mars of 24 hours, 39 minutes, and 21.67 seconds. He also confirmed that the north polar spot was eccentric to the pole.

1783-10 Herschel calculated that Mars' south polar cap is 8.8° from the pole. He also worked out the inclination of Mars' axis to the plane of its orbit, 28°42', and fixed the equinoctial point on the Martian ecliptic (the vernal equinox of Mars) at 19°28' Sagittarius. He deduced that Mars has seasons like Earth, which would account for the changes in appearance of the polar caps, and stated that Mars and Earth were probably the most similar planets in the solar system.

1975-08-20 Viking 1 launched. Viking 2 was launched 20 days later on September 9.

1976-07-20 Viking 1 landed at Chyrse Planitia.

1976-09-03 Viking 2 landed at Utopia Planitia.