Heber of Spain, astronomer

In one of his books, Girolamo Cardano (1501-1576) published a
list of the 12 greatest minds who "excelled all men in the force of
genius and invention": Archimedes, Aristotle, etc.
All but one of these names are easy to identify. The
exception is "Heber of Spain, astronomer."

Can anyone here identify Heber? (My only guess is that
Cardano is referring to the legendary First Monarch
of Ireland, but I can't even find any indication that
Heber was particularly noted for science.)

James