The famous deny Andy 15 minutes of their time

By the standards of the New York parties he adored, and the celebrity rating of visitors to the Factory, his aluminium foil-covered studio on East 47th Street, the occasion was a mite low key: just 1,100 black-tie guests gathered under a white marquee, each of them given a black plastic watch and told, 'This is Your 15 Minutes of Fame'. Somehow though, almost everyone agreed, Andy would have loved it.

Little more than seven years after he died of a heart attack on 22 February 1987, Andrew Warhola, who dropped the 'a' from his last name and blended consumerism, celebrity and the counterculture to become contemporary art's most notorious exponent, had come home, to the city where he was born, the third son of a Slovak immigrant, in August 1928.

Courtesy of the Andy Warhol Foundation and the Carnegie Institute of Pittsburgh, he now stands commemorated by arguably the largest, and certainly the most comprehensive, single-artist museum, on earth. It cost dollars 12m ( pounds 8m), took 18 months to prepare, and contains more Warholiana than an individual mind can absorb.

The famous paintings are there - the silkscreen on canvas portraits of Mick Jagger, Marilyn Monroe and Elizabeth Taylor, the set of 32 Jackies, the Brillo pads and Campbell's soup cans, the Shoes and the Electric Chairs. So is a full collection of the celebrity magazine Interview which Warhol founded, and of his 60-odd films, starting with Sleep from 1963, five hours of the poet John Giorno lying in bed. Then there are Warhol's 'time capsules', those random boxes containing ticket stubs, bills, fan letters - the bric-a-brac identifing an era.

And at Friday night's opening party the era fleetingly returned. Only a few showed up of the really Beautiful People from the 1980s, the 1970s, and the 1960s of which Warhol is most perfectly a part. Jackie Onassis did not come, nor did Jagger or Liz Taylor. Of 'stars' in the conventional sense there was only Dennis Hopper of Easy Rider, plus a clutch of the great and good from Pittsburgh industry and Pennsylvania politics, and some authentic members of World of Warhol.

'He is watching,' intoned Ultra Violet (born Isabelle Dufresne in Isere, France, subsequently a Warhol film star and self-described Spectral Woman), 'but he would have wanted more celebrities, like the Queen of England.' No one however is complaining about the museum: 'tremendous, it's spectacular,' was the verdict of Warhol's pop art colleague Roy Lichtenstein.

The exhibition area is spread over seven floors. A set of five demon-like self portraits, each a different colour, decorates the entrance lobby. The rooms are huge, each display is reverently explained. Take for example the set of Last Suppers, drawn from the Leonardo original, and which had one eminent art critic wondering 'whether a Christian fundamentalist group is planning to open a restaurant.' The visitor however is told that 'for Warhol, Marilyn Monroe is as mysterious and ambiguous as the Mona Lisa'.

What were neither mysterious or ambiguous were Warhol's feelings for Pittsburgh. He hated the place, and left it for New York within a week of getting his college degree in 1948. His fine-honed iconoclasm would have been about as happy in the hidebound smokestack city of those days, as might Salvador Dali had he been forced to spend his life in Birmingham.

But much has changed in Pittsburgh since, including its attitude to its most famous prodigal son. After all, art collections acquired with the Frick, Phillips and other made- in-Pittsburgh industrial fortunes have departed for elsewhere. With Andy Warhol, the process has been reversed.

None are happier than the Warhola family, still liberally scattered around the area. 'Warhola Recycling' reads the faded sign on a scrap metal business on the bank of the Allegheny river, less than a dozen blocks from the museum. It is run by George Warhola, now in his mid-40s but possessing an unmistakeable dash of those Slavic features. Nephew of the artist, he cannot stop talking of his celebrity relative: 'I'm so proud of him, it kind of sends a chill through me.'

George remembers visiting 'Uncle Andy' in New York during the 1950s and 1960s, and helping him paint, stapling pictures to canvas. 'He was such fun to be with. He'd go out and buy a birthday cake when it wasn't my birthday. I asked him why, and he just said, 'It's a nice thing to do.' '

Now history must make its judgement. Warhol has far exceeded his own 15 minute allotment. But will he go down as the most influential artist of the second half of the 20th century, or as self-promoting charlatan? Preserved at the museum is a 1966 note from a teenage fan, typed on a silver-foil card. 'Who are you?' it asks, 'What are you? Where are you going?' The fuss will subside, the questions remain.

(Photograph omitted)