On June 8, Venus will appear as a tiny black dot crossing the face of the sun—a sight no living person has seen. Transits of Venus occur in pairs several years apart, and then vanish for more than a century. The last was in 1882.

Before radar, transits provided a rare chance to calculate the size of planets as well as a range of heavenly measurements. So it was with high hopes that astronomer Benjamin West viewed the June 3, 1769, transit from a platform he’d built on what is now Providence’s Transit Street. He used a three-foot-long brass reflecting telescope that’s now in the John Hay Library, and noted what he saw in a slim volume, An Account of the Observation of Venus upon the Sun the Third Day of June 1769. Rhode Island College—later Brown—gave him an honorary degree, and he later joined the faculty.

In his Account, West outlined his goals: “to discover the distance of the Earth, the Planets and Comets, from the Sun,” and to estimate their size and temperature. “From a knowledge of all these things,” he continued, “methinks we shall have such a demonstration of the existence of a GOD, who made and governs all things, that even the reformed atheist must tremble when he reflects upon his past conduct.”

We Earthlings ask a lot of our planetary neighbors. West sought proof of the Almighty. Today, we scrutinize televised images of Martian rocks for signs of life itself.