SURE, having five presidents on a dais for the first time is historic. But what about an audience of Zsa Zsa Gabor and Arnold Schwarzenegger and Bob Hope?The line of demarcation between Hollywood and Washington has always been a thin one, and perhaps no president has understood the link - the power of image and communication - better than actor-turned-president Ronald Reagan. So it was perhaps fitting that the celluloid famous and the Washington powerful met here this week, under a robbin's-egg blue California sky, to open the Ronald Reagan Presidential Library. It was a well-choreographed paean of pomp, patriotism, and historical presidential circumstance. There was the F-16s' red glare, Charlton Heston's rhetoric bursting in air, and Lee Greenwood rasping out "God Bless the USA," giving proof that Mr. Reagan's legacy (whatever the judgment) is still there. "Just awesome," said one woman after the tributes to Reagan from four presidents had concluded and Mr. Greenwood was thundering his signature song as jets curtsied overhead. Earlier, the adoration had focused on the famous and would-be famous as they took their seats amid the several thousand Reaganites, GOP faithful, and a gauntlet of reporters. Sonny Bono was corralled by autograph seekers as he threaded his way to his seat. Unfortunately for him, most were giggling teenage girls, which won't help him in his bid for the United States Senate next year. As others strode in, the lyrics, "give me some men, who are stout-hearted men," blared from loud speakers. A blimp floated overhead. Stetson-hatted sheriff's patrolled surrounding hills on horseback, hills that were once the backdrop for Hollywood westerns. "Look, it's Arnold," said one woman as Mr. Schwarzenegger arrived to the kind of reception politicians hope for. After somehow fitting through the metal detector, the pectoral actor marched forward as camera crews marched backward. On the dais, the tribute was all to Ronald Reagan. Three past presidents (Richard Nixon, lone Democrat Jimmy Carter, Gerald Ford) and one present (George Bush) stressed positive elements of Mr. Reagan's legacy: staring down communism, helping end the cold war, "ennobling public service," triumphing as a "great communicator." President Bush called his former boss an "American original" who was born in February but whose "heart is the 4th of July." President Reagan, employing some of his patented Main-Street rhetoric, described his library as not a monument to one man or idea but a "time capsule of American growth and greatness." Perched on a mountaintop, the $57 million complex harbors a museum, a public affairs center, and archives that will hold 54 million White House papers - the most of the 11 existing presidential centers. Those documents, to be gradually released over the decades, will help shape Mr. Reagan's place in history. Some Americans are already making up their mind. A Los Angeles Times poll released this week showed that 28 percent of Americans considered Mr. Reagan an above-average president, while 33 percent ranked him below average. There was no such ambivalence here, no talk of Iran-contra, huge deficits, or detached government. Many confessed only to goose bumps. John Olow III journeyed down from Carmel, Calif. "There is no doubt he will be considered one of the greatest presidents," he said. Vernon Grose, a former Reagan appointee in pinstripe suit and sun-shielding cap, sees Reagan's resolute stand against communism as an epochal event. "His," he said, "was the voice of an earthquake."