Can. 202 §1. In law, a day is understood as a period consisting of 24 continuous hours and begins at midnight unless other provision is expressly made ...Can. 1248 §1. A person who assists at a Mass celebrated anywhere in a Catholic rite either on the feast day itself or in the evening of the preceding day satisfies the obligation of participating in the Mass.
In other words, Sunday evening is still Sunday, and the Saturday evening Mass satisfies the obligation not because it is Sunday aready in the Jewish sense, but because the canon explicitly allows it.
“In other words, Sunday evening is still Sunday, and the Saturday evening Mass satisfies the obligation not because it is Sunday aready in the Jewish sense, but because the canon explicitly allows it.”
Ah, well I see. We operate on a liturgical day, which begins at sundown so a Sunday evening Liturgy could never be a Sunday Liturgy, but it could be a Monday Liturgy.