Asterios’s name day is May 20, the feast of Alexander and Asterios.
Churches that follow the Old (Julian) Calendar keep the same feast on June 2 of the civil calendar. See everything commemorated on May 20.
The saint behind the name
Alexander and Asterios
May 20, Martyr, Αλέξανδρος και Αστέριος
Alexander and Asterios were among the executioners of Saint Thalleleos at Aegae who, seeing the wonders that accompanied his torments, confessed Christ themselves.
Also celebrating on May 20
These names share the feast, many of them other forms of the same name:
What to say on a name day
The Greek wish is Χρόνια Πολλά (Chronia Polla), “many years.” A call or a short message on the day is what people remember. See name day wishes you can send and what a name day is.