Can a Roman Catholic attend an Orthodox Mass and have it fulfill his Sunday Obligation?

Can a Catholic ever attend an Orthodox Liturgy instead of Sunday Mass, and could Catholics receive the Eucharist there as well? Let’s investigate…. First, let’s check Canon law. From the 1983 Code: 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. So now the question is, “Do the liturgical celebrations on orthodox parishes constitute “Catholic rites?” No, Orthodox liturgies are not a "Catholic rite" But, even though an Orthodox liturgy is Non-catholic, the Catholic Church does recognize the VALIDITY of the sacraments administered to the Orthodox faithful by Orthodox clerics, because it holds that the Orthodox clergy, unlike the clergy of various protestant denominations, are validly ordained priests. In case you don’t know, here are the definitions of valid and licit: 1 - VALID - When a sacrament has proper Matt...