Gellio Sasceride (Sasserides) (1562–1612) was a Danish astronomer and doctor. Sasceride worked as an assistant to Tycho Brahe after studying under him. It is believed[1] that the following words were written by Sasceride to Brahe: Quia adhuc aliquid superest spatii, quae sequuntur paucula, sic expetente typographo, subiungi permisi ex literis cuiusdam medicinae Doctoris, Patavii commorantis, ad quendam studiosum Danum.
Sasceride was also friends with Galileo. On December 28, 1592, after Galileo had begun his studies, he wrote a letter to Sasceride (at the time no longer Brahe's assistant) with the words Exordium erat splendidum ("[my] debut was excellent").[2] In 1590, Sasceride had sent to Galileo the only copy of a book until then found in Italy detailing the heliocentric system.
The crater Sasserides on the Moon is named after him. It lies near Tycho, named after Tycho Brahe.