The best way to celebrate modern dance history? By dancing it, of course

How long does it take to become history? Antique dealers say it takes 100 years. Sociologists start the countdown at yesterday. Whatever the answer, it's safe to say that these days events become legendary faster than they become history.

The Judson Dance Theater, a revolutionary-minded association of dancers, composers, and visual artists, reached its peak of activity in the mid-1960s. That's not long ago, and much of the movement's attitudes toward art are still current. We still have minimal and conceptual painting. In dance, we still see choreography composed of ordinary movement for ordinary people. We still see dances that are actually not more than ideas-in-motion.

If the Judson dance movement (so-called because headquarters were at the Judson Church in Greenwich Village) isn't history as such, it certainly is a legend. The Judson days are viewed not only as a time of innovation and influence, but more crucially as an instance of artistic community, where an odd assortment of freewheeling types functioned in common sympathy and support.

It's under the halo of legend that a retrospective of the Judson movement took place recently -- not at the Judson Church itself but at St. Mark's Church, which is a current arena of experimental art. Divided into two programs, the reconstructions gave a sampling of Judson artifacts performed by a few of the movement's stars but mostly by their acolytes. Typically Judson were the crazy mix of works and the wild range of quality. No matter. The audience had come to a shrine and, by golly, they were going to worship. Ovations galore!

What did we see? Well, we saw Philip Corner play the piano with his feet, Yvonne Rainer dance what some people term a seminal solo called ''Trio A,'' a bunch of kids rush at each other in rough and tumble play, a pseudo-horror movie by Brian DePalma, two men flipping each other to the floor with the suavity of Astaire and Rogers. In ''Pop 1'' Edward Bhartonn back-flipped onto a balloon and crushed it. Later on in the evening he back-flipped and, missing the balloon, moved over a bit and then crushed it. That dance was called ''Pop 2.''

Perhaps it's because of the campy outrageousness of the ''Pop'' pieces that they were the hit of the retrospective. What does that say about current sensibilities, however? Is camp humor the true legacy of the Judson movement? And what does it say about the rest of the program?

In truth, there were other moments of nutty inspiration. In ''Carnation'' Lucinda Childs sat calmly at a desk and put a vegetable steamer on her head, fashioning a hat. Then she fashioned pieces of sponge into sandwiches. After assembling her meal, she stuffed the innards of the sandwiches into the holes of her steamer hat, transforming it into quite a snazzy chapeau. Childs then found other curious things to do with other curious props. The point is that whatever she did turned out to be elegant.

Remy Charlip's ''Meditation'' provided an elegant eeriness as he contrasted almost grotesquely emotional facial expressions with the quietude of his body making delicate line drawings in space.

When all was tallied, however, it was difficult to reconcile the raw data with the legend. But perhaps no art movement can be understood by its raw data. Context may be everything.

The real point of the Judson days may not be what the artists made but how they felt about what they were making. The Judson retrospective dug up a certain period of time but could not take us back into the spirit of that time.