The Met's 'real' opening - a Birgit Nilsson triumph

The Metropolitan Opera may have officially opened with Bellini's ''Norma'' back in September, but for most opera lovers the real opening night occurred Oct. 12 with the revival of Strauss' massive ''Die Frau Ohne Schatten'' (''The Woman Without a Shadow'').

It was a much-needed boost to the company and to operagoers. The first five productions of the season had ranged from feeble to fiasco - then along came ''Frau.''

The big news for local audiences was Birgit Nilsson's first appearance at the Met as the Dyer's Wife, though she has sung it all over Europe and last season in San Francisco. The other news, of sorts, was that this revival would be the first in which Leonie Rysanek - the Met's first Empress in 1966, and the soprano who has unquestionably owned the role for the past 27 years - would not be scheduled to sing.

''Frau'' is Strauss' and librettist Hugo von Hoffmansthal's attempt to write the ultimate mythical opera. The shadow is symbolic of maternal desires: The otherworldly Empress, married to a mortal, wants a shadow; the Dyer's Wife has one for grabs. It is the drama of these two women coming to terms with love and selflessness that animates ''Frau.'' The more frequently one experiences this opera, the more remarkable becomes the achievement, on a mythic and human scale. Overall, it is slowly being recognized as Strauss' most extraordinary opera (and , increasingly, most beloved).

Ironically, this ''Frau'' revival was not in the original plans for this season. Two seasons ago, ''Frau'' had been deemed out of the question unless a season was planned around it. Then the ''Gotterdamerung'' casting fell through this past summer and suddenly, there was ''Frau,'' which has become the only acceptable Met-standard evening of the season to date.

Miss Nilsson, a self-proclaimed sexagenarian, made every moment of the Dyer's Wife count. From exceptional beginning to taxing end, this is a big performance , conceived on a heroic scale, executed with remarkable reserves of power and great depths of tragic feeling. Some areas of the voice sound not as reliable as they were 10 years ago, but at the Met, her rough patches were far fewer than in her performance in the same role in San Francisco last season. And here she fits into the large production with ease and gets all her dramatic points across with force. And to think that after the ''Elektra'' two seasons back, all they were able to offer this legend was a few concerts!

Eva Marton, the ''new'' Empress, also did not tire, in an equally forbidding role. Miss Marton does not have an intrinsically warm tone, but she has all the power needed and the ringing freedom up top to sustain the treacherously high dramatic soprano role. In the final scenes, where the Empress has to become almost mythic vocally and histrionically, Miss Marton fell short of the mark, but we are fortunate to have so generally accomplished a singer as she to do this role. And surely nothing in her Met career - even Chrysothemis in Strauss' ''Elektra'' - indicated she had this much in her.

The Nurse has an important role, and for executing her duties to the last slavish letter she is consigned to perdition. Mignon Dunn sang the role quite well - aside from a few battle-cry whoops masquerading as notes. And more to the point, she held her own on the stage with force and conviction.

With the exception of Franz Mazura, outstanding as Keikobad's Messenger, the men in the cast did not hold up their share of the evening.

Down in the pit, Erich Leinsdorf seemed to be trying to make amends for his listless Wagner. The majesty of Strauss' score, the colors and the textures, were always gloriously audible. What Leinsdorf's reading lacked in sheer passion it made up for in clarity, in delicacy, and grand drama.

Occasionally the orchestra let him down, as in the agonizingly prolonged cello solo beginning the Emperor's big ''Falcon Scene.'' And in the finale, he seemed to lose sight of the shape, and the build toward the last climax.

Most of the productions unveiled in the first season at the new house in 1966 have either worn out or are now on their last legs. This ''Frau'' (along with ''Peter Grimes'') is a glorious exception. Director Nathaniel Merrill taxes every facility the Met backstage has - the elevators, turntables, lights - and brilliantly translates into theatrically bold gestures all the effects called for in the score. In what has to be his best work at the Met to date, lighting designer Gil Wechsler illuminated and complemented the Robert O'Hearn sets, rather than obscure them as he did last time around. In all, it was fitting tribute to the conductor who originated the opera at the Met and led all performances there until now: the dedicatee of the revival, the late Karl Bohm.

Unfortunately, only five ''Fraus'' have been scheduled this season, and needless to say the four Nilsson performances have been sold out to the rafters (except, of course, standing room, which goes on sale the day of performance). But at least an evening of genuine opera is back on the Met stage, and the audience gathered let the artists involved know in the kind of prolonged, vociferous ovations that used to be the norm and are now the greatest of exceptions.