Since its founding in 1891, many people have passed through the doors of the Vatican Observatory. A quick perusal of our guestbook reveals several Names, including Popes, nobel laureates, astronauts, actors, and saints.
Today's guestbook entry is from May 4, 1910, when H. G. van de Sande Bakhuyzen made a visit.
Next to his name, Hendricus Gerardus van de Sande Bakhuyzen (1838-1923) wrote simply, "Leiden."
He was the director of the Leiden Observatory in the Netherlands from 1872-1923. Most of his research dealt with asteroid observations. He also made the connection between the comet 3D/Biela and a meteor shower.
There is a crater on Mars named Bakhuysen in his honor, due to his publication of drawings of Mars made by Johann Schroter.