PERHAPS THE GREATEST THING ABOUT Galileo Galilei’s first publication, translated from the Latin as The Sidereal Messenger, is his sense of adventure at being the first known human to telescopically observe and painstakingly chronicle the night sky.
Galileo recorded his unprecedented experience in 1610 CE, a time of adventurous European discoveries in general. His detailed and methodical observations will be thrilling to anyone also observing the same celestial sights for the first time through a simple 20x (read: low-power) backyard telescope. Science historian Albert Van Helden’s superb 1989 translation reveals Galileo’s excitement and wonder on every page, and adds valuable context via explanatory bookending and notes.
That era being one of grand aspirations and flowery speech, Galileo’s grateful bow to his patron, Duke Cosimo II de Medici, is fully titled, “SIDEREAL MESSENGER, unfolding great and very wonderful sights and displaying to the gaze of everyone, but especially philosophers and astronomers, the things that were observed by GALILEO GALILEI, Florentine patrician and public mathematician of the University of Padua, with the help of a spyglass lately devised by him, about the face of the Moon, countless fixed stars, the Milky Way, nebulous stars, but especially about four planets flying around the star of Jupiter at unequal intervals and periods with wonderful swiftness; which, unknown by anyone until this day, the first author detected recently and decided to name MEDICIAN STARS.” (That honorific didn’t stick; instead, the “four planets” are now called by astronomers the “Galilean moons.”)
Let us skip Galileo’s five-page introductory paean to the Duke de Medici and dive right into the first paragraph of the work itself:
In this short treatise I propose great things for inspection and contemplation by every explorer of Nature. Great, I say, because of the excellence of the things themselves, because of their newness, unheard of through the ages, and also because of the instrument with the benefit of which they make themselves manifest to our sight.