"Hollywood: Legend and Reality," a huge history of America's love affair with the movies, opens today in the Smithsonian's National Museum of American History. Curator Michael Webb, former American Film Institute Theater director, presents filmland in equal parts method and magic. The show shines brightest at the seven video stations where clips of 44 movies unroll. These greatest hits of 1923-1982, neatly arranged in both miniature theaters (one a make-believe drive-in) and kiosks, divide Hollywood history into scenes. So much for legend.

*Reality opens the magician's box and disassembles it for us in 200 objects. King Kong is revealed as an 18-inch-high jointed metal skeleton, clothed in fur. C3PO from "Star Wars" turns out to be a golden suit of armor for an actor. And the magnificent Gozer Temple of "Ghostbusters" is hardly bigger than a child's dollhouse, though fearsomely and frighteningly adorned with gargoyles. The piano from Rick's Cafe in "Casablanca," though thankfully full-sized, looks far too bright and new to have the proper seedy quality expected. The spaceship from "Close Encounters of the Third Kind" turns out to be only a picnic-sized pie in the sky. But even in miniature, all its little lights glitter and gleam, and inside are wonderful beings coming to rescue us all.

Not all of our dreams are shattered by the reality. The costumes are truly magnificent, though their tiny waists show how stars must have suffered for their public. Even Mae West's later well-known voluptuousness is belied by her gown from the 1933 film "I'm No Angel." Rudolph Valentino's bullfighter "suit of light," a work of art in itself from "Blood and Sand," shows the swashbuckler as much smaller than he appeared. Jeannette MacDonald's pearl-encrusted red velvet by Adrian for 1937's "Maytime" almost bursts with song. Shirley Temple's shoes next to Fred Astaire's well-shined bigger ones look as though they may begin to tap at any moment. The high-slit dress made of fur and sequins that Ginger Rogers wore in "Lady in the Dark" is indeed the stuff of which dreams are made.

Webb points out that the spectacular Viennese poster of Greta Garbo as a gold head looms through the glass of an exhibit that holds her court dress from "Queen Christina" (1933), and is punctuated by the exclamation of the Oscar figure ("which she should have won") in the foreground.

The 200 photographs represent the first time that the archives of Time Inc. have been made freely available to an exhibit curator, according to Zachary P. Morfogen, cultural affairs director for Time. The corporation sponsored the exhibit together with the Smithsonian Institution's Traveling Exhibition Service (SITES). Many glamorous faces, made up to the last eyelash, shine forth from the wall. But some of the more interesting displays are those that show the process of movie making, such as the cutaway of the house set for "The Diary of Anne Frank" and a picture of an unbelievable set for "The Thief of Baghdad," which Webb calls the largest set ever made.

Hollywood as an inspiration for art is exemplified in a few sculptures and paintings, which somehow seem almost lost among the other artful devices. Marisol's Bob Hope as a block of wood ornamented by a nose, Reginald Marsh's tempera painting "A Paramount Picture" and Edward Hopper's affecting "New York Move" are only the beginning.

The posters are themselves a people's art of very high quality. Unfortunately, they also show how much better the Swedes, Poles and Viennese are at posters than the Americans. One of the posters especially commissioned for the show, a montage of star faces, is illustrative of how little impact some posters can have.

Don't expect to make it through the show in a hasty walk. If you allow yourself to even peek at one of the framed documents, you'll be lost for the day. One touts George Raft for the Bogart role in "Casablanca." In another, David Selznick cables he's through filming "Gone With the Wind" and everyone can go to the devil.

The show, designed by Stuart Silver and Michael P. Donovan, takes numerous trucks to transport it. Even so, after it closes here June 15, it will go on to the Cooper-Hewitt Museum in New York, then to Miami, Cincinnati, Denver, Los Angeles and some foreign engagements, said Peggy Loar, SITES director. The book of the same name, edited by Webb, may be the best screenplay on the industry yet.