Guido Horn was born in 1879 in Trieste, which was at the time under the Austro-Hungarian empire.  During World War I he added "d'Arturo" to his name (in tribute to both his father and the brightest star in the Bootes constellation) to make it sound more Italian, before deserting the Austrian army and joining the Italian army as a volunteer.

Horn d'Arturo graduated from Vienna University in 1902 with a thesis on the orbit of the comet 1889IV. He then worked at the Observatories of Trieste, Catania, Turin and Collegio Romano before finally settling in Bologna in 1920 where he held the Chair of Astronomy.
As a Jew, he was removed from the University in 1938 due to racial laws, but was reinstated in 1945.
He died in Bologna in 1967.

Horn d'Arturo can be credited with reviving the fortunes of Astronomy in Bologna in the 1900s; after the brilliant achievements of the Specola in the 1700s under Eustachio Manfredi there had followed a gradual decline in the 19^th century. Horn d'Arturo was a polyglot and great humanist, gifted with both brilliant scientific intuition and organisational skills, which he put to use in three areas in particular: instrumentation, research and publications.