This just in via Whispers in The Loggia:
In another significant liturgical turn at the very top, B16 will celebrate tomorrow's annual Sistine Chapel Mass for the Baptism of the Lord in the ad orientem stance -- that is, facing away from the congregation and toward the cross that stands at the chapel's back wall.
In an explanatory note from the Office for Papal Liturgical Celebrations picked up by the Italian wires, the papal MC Msgr Guido Marini announced that the Mass, to be conducted according to the post-Conciliar "Ordinary Use" approved by Paul VI, would employ the main altar of the Sistina. As a result, the note said, "at certain moments the Pope will have his shoulders [back] to the faithful and his gaze toward the Cross."
As the chapel's original altar is not freestanding, versus popolorum celebrations there have required the construction of a temporary altar and platform. While John Paul II celebrated his first Mass after his 1978 election using the permanent altar and no freestanding altar exists in the Pope's private chapel, a public papal liturgy has not been celebrated using the "common orientation" in recent memory."The celebration at the old altar is being restored so as not to alter the beauty and harmony of this architectural jewel," the note said, "preserving its structure from the celebratory point of view and using an option contemplated by the liturgical norms."
The change of orientation, Marini's statement said, would seek to enhance "the attitude and disposition of the whole assembly."The annual liturgy features the baptism of several infants by the pontiff. The contemporary baptismal font designed by Lello Scorzelli -- also the designer of the pastorali, the cross-topped liturgical staffs used by Paul VI and his successors -- will likewise be maintained.
Here is a picture of the event for your enjoyment (or not depending on your ideas of what the Liturgy should be.