Here is a piece from Catholic News Service about ad orientem celebration of Mass.
Let’s have a look with my emphases and comments.
Not exactly ‘ad orientem’
Some media are reporting that Pope Benedict celebrated Mass “ad orientem” — facing toward the east — last Sunday when he used the Sistine Chapel’s historic main altar for the first time in decades.
That’s not literally correct. In fact, it’s off by 180 degrees. Because the chapel’s altar is built on the western wall, the change meant the pope was facing west during much of the liturgy. [This is geographically accurate. But that is decidedly not the point. The theological point is that when the congregation and priest face the same directions, no matter what the compass point is, they are facing the liturgical East. That is what ad orientem means.]
On the contrary, “ad orientem” was the direction popes faced when they used the free-standing portable altar in the Sistine: the celebrant faced east when he faced the people. [Again, the compass point is really not the point.]
I spoke the other day to Msgr. Enrico Vigano, who has worked many years in the Vatican’s liturgical office, and he agreed that the term “ad orientem” doesn’t make sense in the Sistine Chapel. [Maybe literally.]
Instead, he said, his office made reference to the cross, which stood on the main altar, framed by Michelangelo’s fresco of the Last Judgment. The idea here — and it’s one Pope Benedict has made in the past — is that when the pope and the people face the cross together, it emphasizes that the Mass is a common act of worship. [Well... maybe. However, Papa Ratzinger is very carefull in pointing out in his writings that ad orientem worship is extremely important and that if one cannot have ad orientem worship, one can at least have the Cross in a position between the celebrant and the altar so that it becomes the point of focus. So, for Pope Benedict, it is best to have ad orientem worship with the congregation and priest facing the Cross together, but as second best one could have the Cross between the people and priest in a prominent way. This is explained by Papa Ratzginer in one of my PODCAzTs.]
In early Christian churches, facing the cross coincided with facing east, the direction of the rising sun and, in a figurative sense, of the resurrection and the second coming.
But the Christian tradition of worshipping “ad orientem” faded, and over the last 500 years many churches have been built facing different directions, including one not far from the Sistine Chapel — St. Peter’s Basilica, which also faces west. [That's right. Mostly because people had the flexibility of mind to understand that facing the liturgical east was the point, not necessarily facing the eastern compass point. Also, St. Peter's had to be built in the way it was, because of the shape of the Vatican Hill.]
Whatever a church’s compass orientation, some have wondered whether the papal Mass last Sunday marked the beginning of a trend. Are we going to see a Vatican effort to turn all the altars back to the pre-Vatican II position? [Well... the point of a "trend" is that there are more than one instance, right?]
Probably not. Pope Benedict weighed in on this when he was a cardinal. He said he agreed with theological arguments for the priest and the people facing the same direction, but thought it would leave Catholics more confused than ever if the altars were turned around again. [This is not entirely accurate. He said that it would not be good to confusion through abrupt changes. When it would be not possible to implement a shift to ad orientem celebration quickly or without confusion, then it would be better to place the Cross in the center. The point is that he wanted to avoid the sort of confusion that abrupt changes caused decades ago.]
“Therefore, I’m not aiming at a practical application at this time,” he said.
That was in 1993, however, and one big thing has changed: he’s now pope.
While this article was not entirely negative, I think it tugs the readers understanding in the wrong direction.