LIKE the Hale-Bopp comet, Studio 54 is a highly visible phenomenon with a tail that just won't quit. After nearly 20 years, people still sense the afterglow and lopsided ideals of the place, which celebrated exclusivity as a spectator sport, among other things.
The most recent outbreak of Studio 54 nostalgia occurred Wednesday night. In conjunction with the publication of ''The Last Party: Studio 54, Disco and the Culture of the Night'' by Anthony Haden-Guest, there was a photography exhibition opening at the Serge Sorokko Gallery in SoHo. And just for old time's sake, there was a scene at the door.
''I have friends out there who are never going to forgive me for this,'' Mr. Haden-Guest said as he looked out at a mob of guests kept out of the overpacked gallery by bouncers. If he seemed more pleased than chagrined by the sad spectacle, it may have been because bad door scenes are usually good for book sales.
And this door scene was bad. Tina Louise was shut outside far too long for a ''Gilligan's Island'' icon. Richard Johnson, the editor of The New York Post's Page Six, was stuck outside for a while, too, even though his wife, Nadine Johnson, was promoting the party. Robert Altman couldn't get in either. What could be more delicious than looking out on someone that important among a crowd being squished against the gallery window like insects on a windshield?
''This is a picture right here,'' said Ron Galella, who was one of many paparazzi enjoying the strange sensation of being an honored guest instead of a quasi-nuisance. His pictures of Truman Capote, Andy Warhol and Olivia Newton-John were on display, along with pictures by Irving Penn, Diane Arbus and Elliott Erwitt. People were even taking his picture. He didn't mind. ''I'm not afraid to have my picture taken,'' said Mr. Galella, who was sued by Jacqueline Kennedy Onassis in the 1970's for invading her privacy.
Nostalgia was as thick in the air as disco fog. It was a night for recalling Bianca Jagger on a white horse and Halston on drugs, a night for using the term Eurotrash as a compliment, revering defunct clubs and lamenting the current quality-of-life laws that are changing the nature of night crawling. Although the invited guests Liza Minnelli and Brooke Shields did not show up, Gloria Gaynor did, as did Fred Schneider of the B-52's; Nikki Haskell, who once gave a party for Michael Jackson at Studio 54 and now sells a line of diet candies called Star Suckers, as well as some sort-of-supermodels, retired disk jockeys, gossip industrialists and many, many others.
There was even one child, Melanie Judson, the 2 1/2-year-old daughter of Robin Platzer, a party photographer. While mother reminisced, daughter sat at the gallery's front desk talking on the phone like a little party promoter in training.
''She's a people person,'' her mother said. Better that than a club kid.