They have taken their lunch hours and called in sick from work to slip over to the Uptown Theater, to join the crowds lining up on Connecticut Avenue to see "Star Wars," the new science-fiction action movie that set an opening day record for the Uptown Wednesday.

"Star Wars" grossed $12,898 at the Uptown in its first day, a figure exceeded only be theaters in New York, Los Angeles and San Francisco. Representatives of 20th Century-Fox, the film's distributor, said the film was breaking opening-day records everywhere.

E. Charles Costolo, a district manager for RKO-Stanley Warner Theaters, which owns the Uptown, said the previous first day record for a film at that theater was held by "Fiddler on the Roof," which had a 56-week run. "Star Wars" also bested the first-day mark posted by "The Exorcist," which went on to establish the current record for an opening week after it opened at the 750-seat K-B Cinema Dec. 26, 1973. "The Exorcist" grossed $7,779 the first day.

The Uptown holds 950 persons Costolo estimates about 4,500 moviegoers attended the six opening-day showings, a bit more than 92 per cent capacity.

At yesterday's 1 p.m. matinee, which appeared to be closer to 75 per cent full, an enthusiastic crowd cheered when the confrontation between Good and Evil was decided for the good guys in the film.

Costolo said about 2,000 persons had to be turned away from the evening showings Wednesday, and only the 3:10 and 5:20 p.m. performances were not sold out. An extra late show was added at 11:50 to accommodate the demand for tickets.

Contemplating the start of summer vacation, Costolo remarked, "We haven't scratched the surface as far as matinee business is concerned."

Yesterday's matinee business was brisk, however, for a balmy Thursday afternoon. A man in his 20s who called himself a "science-fiction nut," had taken sick leave and didn't want his name in the newspaper.

Other, like a group of eight computer systems analysts from the University of Maryland, took advantage of their lunch break.

It's one of the best," said Tom Sherren, one of the computer expers, who said he has seen a few sci-fi's. "We almost sat through it a second time."

Many of those coming into and going out of the theater said they had seen previews of the movie weeks in advance or had been influenced by the rave reviews in the newspapers or news magazines.

A 20th Century-Fox opening-day record was set in New York, where the Loews Astor Plaza theater grossed $20,322 with "Star Wars." John Burke, the manager of that theater, said more than 23,000 persons went through the turnstyles there in six showings. The Astor Plaza, on the West Side near the Broadway theater strip, seats 1,525.

"Star Wars" has had an impact also on the neighborhood of the Uptown: A new pub on the block reportedly did a boom business Wednesday, and some neighbors are complaining that the crowds cause parking and litter problems in the neighborhood.