Milestones in Astronomy: 1671 to 1801

In early astronomy, scientists discovered many different moons and identified different celestial bodies in the Solar System. Mathematicians and physicists came in handy to explain the things that were seen. During the 1700s, Charles Messier and Sir Frederick William Herschel led the way for future astronomers. In this article, you will also learn more about the first asteroid.

1671 , Between 1671 and 1684, Giovanni Cassini discovers four moons associated with Saturn. The Italian/French astronomer and mathematician also made successful measurements of longitude using a method established by Galileo. He used eclipses of Jupiter’s satellites as a clock. Cassini served as an astronomer at the Panzano Observatory from 1648 to 1669.

1687 ,  Isaac Newton shares his theories of planetary motions when he publishes his thoughts.

1705 , Edmond Halley predicts the return of a comet that is later named after him. To learn more about his discovery and theories, read the article titled, ” The Appearances of Halley’s Comet.”

1774 , Charles Messier begins a compilation of stars that he keeps in catalogue form. The French astronomer writes about deep sky objects, such as star clusters and nebulae. Messier started the catalogue so that other observers of astronomy could benefit. He was a comet hunter and wanted to help people tell the difference between objects in the sky that were permanent from those that were fleeting.

1781 , Sir Frederick William Herschel makes a discovery of the seventh planet in the Solar System, which is named Uranus. The British astronomer who was born in Germany also discovered two of the major moons of the planet , Titania and Oberon, which were named after characters in a William Shakespeare play. From 1787 to 1789, Herschel discovers two moons belonging to Saturn.

1801 , The first asteroid is identified. It is named Ceres and was found by Giuseppe Piazzi , an Italian Catholic priest that belonged to the Theatine order. As an astronomer and mathematician, Piazzi discovered what is now known as the largest member of the asteroid belt. On the first of January, 1801, Piazzi described the asteroid as a ‘stellar object” that traveled against a backdrop of stars. He first thought he had found a fixed star, but later noticed its movement. He dubbed this find “a new star.”

When describing Ceres, Piazzi wrote in his journal: “The light was a little faint, and of the colour of Jupiter, but similar to many others which generally are reckoned of the eighth magnitude. Therefore I had no doubt of its being any other than a fixed star. In the evening of the second I repeated my observations, and having found that it did not correspond either in time or in distance from the zenith with the former observation, I began to entertain some doubts of its accuracy. I conceived afterwards a great suspicion that it might be a new star. The evening of the third, my suspicion was converted into certainty, being assured it was not a fixed star. Nevertheless before I made it known, I waited till the evening of the fourth, when I had the satisfaction to see it had moved at the same rate as on the preceding days.”