Career
In 1985 he served on a team involved in using the Hubble Space Telescope in a study that focused on Transition Comets -- Ultraviolet Search for Ohio Emissions in
He was the first amateur astronomer to obtain precise astronometric positions of minor planets using a charge-coupled device camera. He is a prolific discoverer of asteroids, and minor planet 7132 Casulli is named in his honor. 9121 Stefanovalentini
Casulli discovered Asteroid 9121 Stefanovalentini on 24 February 1998 at the Colleverde Observatory in Italy.
lieutenant is a main belt asteroid named in honour of amateur astronomer Stefano Valentini.
93061 Barbagallo
Casulli and Ermes Colombini discovered asteroid 93061 Barbagallo on September 23, 2000. Its provisional designation was 2000 SX20.