Copernicus Begins a Promising Career - March 09 / Today in Science / Science NetLinks

On March 9, 1497, Nicolaus Copernicus' first recorded astronomical observation took place. From the article:

"March 09 Today In Science

Copernicus Begins a Promising Career
Nicolaus Copernicus (1473-1543) recorded his first astronomical observation on this day in 1497. Studying religous law in Bologna, Italy, Copernicus, who was living in the home of an astronomer, noted the moon eclipsing the star Aldebaran. This was to be the first of many astronomical observations he would make.

With a firm grounding in mathematics, Greek, astronomy, and medicine, Copernicus began to devote much of his leisure time to studying the heavens. In 1512, he wrote Commentariolus, a short paper positing that the earth rotated around the sun, and not vice versa, as earlier scientists (Ptolemy, in particular) had suggested. He did not publish the work, but did circulate a certain number of hand-written copies. During the decades that followed, he fleshed out the ideas in his manuscript, De Revolutionibus Orbium Coelestium, fully embracing and advocating for an understanding of a heliocentric (sun-centered) view of the solar system. It also included theories relating to solar theory, the motion of the moon, and planetary latitude and longitude.

Although he received a printed copy of his life work while on his death bed (his student had convinced him to publish it and then shepherded it through the process), The Father of Astronomy would not live to see his work merit the attention it deserved."