The Terra Museum of American Art has just opened its new quarters with a special exhibition, ``A Proud Heritage: Two Centuries of American Art.'' The Terra thus completes the first part of its three-phase, $75 million building project that ultimately will include a 700-seat concert hall and expanded museum facilities on ground still occupied by various commercial properties.
The second phase is expected to begin in 1989, and plans for the third will be announced after the completion of the second.
At this point there isn't much one can say, except to note that the initial structure is quite handsome; that the opening exhibition of works from the Pennsylvania Academy of the Fine Arts is well worth a visit (it closes on June 21); and that the museum's objective, to ``continually reevaluate the heritage of American art,'' is a good one. Beyond that, one can only wait and see.