New York — It was an explosive opening night at the opera. Some 75,000 appreciative listeners cheered the Metropolitan Opera cast and delighted in the spectacular fireworks display as Handel's ''Rinaldo'' was performed in Central Park Tuesday night.
Picnickers sprawled on blankets, parents with teen-age children, and fans straight from the office with loosened ties and stocking feet took advantage of perfect weather and the largess of New York City, Chemical Bank, the National Endowment for the Arts, and several foundations to attend one of the many free cultural activities offered throughout the City during the summer.
Hundreds of thousands of New Yorkers and tourists will visit museums, see theater, and listen to jazz greats as New York shows its cultural heart this summer. Some of the programs are presented by the city and receive funding from corporations and foundations. Others are small-budget operations begun by people who want to open the arts to those who might not otherwise attend.
For example, Katharine Fehl is codirecting a production of ''Romeo and Juliet'' at the Boat Basin Theater in Riverside Park on the Hudson River. The engagement will end this Sunday.
''I like the idea of people seeing a straightforward production of Shakespeare,'' she says, adding that she feels a lot of the Bard's work is overproduced. Ms. Fehl points out that Broadway tickets, which are often in the
''People expect things in the park to be free,'' she comments. But because of this, the production has a $7,500 debt, and the audience has been asked for contributions, says Ms. Fehl, who is artistic director of the Pelican Theater.
Actor Jeremy Irons will read from some of his favorite writings during the lunch hour at St. Bartholomew's Episcopal Church next Thursday. It will be part of a free series presented by Stanley Eugene Tannen's Free Theatre Productions.
By being free, the performance is opening doors, Mr. Tannen says. ''It enriches the lives of young people, and reaches senior citizens who couldn't afford to go. Some of these people have never seen live performances.''
And in the long run, the hope is that people will read more or go to theater more, he adds. The hope of future subscribers is also one reason that the Met gives eight performances in parks in all five boroughs for two weeks during the summer, says a spokeswoman. She estimates that some 500,000 people attended the programs last year.
Renee Levine of the National Endowment for the Arts points out that such programs as Lincoln Center Out of Doors ''does attract a lot of people who wouldn't get gussied up to go inside. But the hope is that a person will take a child or a friend and go in to buy a ticket.''
The New York Visitors Bureau has a calendar of summer events, which includes walking tours of Grand Central Station, special hours at such museums as the Whitney and the Museum of Natural History, and children's events in the city's parks.