Two photographs distributed by the Associated Press on Jan. 28 and said to show the family of teacher Christa McAuliffe reacting to the breakup of the space shuttle Challenger were erroneously captioned, the news agency has determined. The AP captions said the photos showed the family reacting to the shuttle disaster. One of the pictures appeared on the front page of The Post Jan. 29; the caption was rewritten in late editions to indicate the family was responding to the flight and not necessarily the shuttle explosion. After a Boston Herald report Thursday about the photographs, the AP said it compared its photographer's film with an unedited videotape of the McAuliffe family during the launch. The news agency said it found the photos were taken after the Challenger liftoff but before the shuttle exploded.

"We were rejoicing in the liftoff. We were exalting in it. We were celebrating with her. Then it stopped. That's all. It stopped," said Concord High School principal Charles Foley, his voice shaking.

During an emotional news conference this afternoon, Foley stood in the auditorium where, hours before, students with party hats and noisemakers had subsided into stunned silence as they realized, slowly, that the shuttle carrying Concord teacher Christa McAuliffe had exploded.

The horrifying moment when Challenger lifted off gloriously and burst apart was witnessed on television by schoolchildren, office workers and families throughout McAuliffe's town. The excitement that had swelled here since July when McAuliffe was selected as the first teacher in space turned to shock, and shock to grief.

The flight's terrible miscarriage also evoked resentment from some students toward reporters and camera crews who periodically disrupted their lives over the last six months and made their misery a public spectacle today. When the extent of the disaster became clear, a voice on the public address system asked students to return to their classrooms and news people to leave the building.

Dismissed early, some of the departing students declined to give their names, others to speak at all. "It's pretty hard to handle," one boy said.

"It's a terrible, terrible loss for us," Foley said this afternoon, pleading that reporters understand our "extreme feelings of emotion." His face reddened, and a colleague sitting beside him on the stage squeezed his arm in support. The principal went on to say that, with classes canceled Wednesday, the faculty would gather "as sort of a family unit" to consider how to deal with the tragedy.

Foley said he hoped that McAuliffe, who seemed to charm everyone she met with her good nature and enthusiasm, would be recognized "as the heroine we believe she is."

McAuliffe had intended through her televised lessons from space, scheduled for late in the shuttle mission, to "demystify" the space program in what she called "the ultimate field trip."

Today, Foley said, she may have taught the youngsters a tougher lesson about life.

"There is nothing that is perfect. There is nothing that is predictable," Foley said.

Asked if he would recommend that other teachers apply to the space program, Foley hesitated momentarily before replying quietly, "Sure."

Foley has scheduled a second session with reporters Wednesday. Today's news conference, well and hastily organized despite his obvious sorrow, reflected the skill he has acquired the hard way in dealing with the media. He asked reporters to show "respect for our privacy today and in subsequent days . . . ."

The explosion was the second event in two months that has brought catastrophe and publicity to the school.

In December, a 16-year-old dropout, Louis Cartier, took two students hostage and held police at bay in a stairwell at the school before he was fatally shot by police. Today, the psychologist called in to help the students deal with that shooting came back to help plan counseling for the students after McAuliffe's death.

Psychologist Norman Shulman said resolving their grief "is going to be more difficult" this time because McAuliffe was so well known and admired. Foley said he expects counselors to tell his students that "it's okay to feel bad about this. It's okay to feel sorrowful. It's okay to cry."

McAuliffe had been expected to talk from the shuttle with a few high school students here. Beneath a large satellite dish on the roof over the school's main entrance, a large poster read, "Skymaster is bringing Christa down to Earth."

The whole town seemed to have paused this morning to watch what they thought would be a thrilling moment of history, when McAuliffe was borne away from Earth.

Instead, one woman said, "It was like your blood ran cold." On her desk in City Hall, the woman had tucked an official NASA portrait of McAuliffe into a notebook, leaving visible only a sleeve of McAuliffe's sky-blue NASA jumpsuit and a row of stars on the American flag in the background.

City Manager James C. Smith, who had been a member of a homecoming committee for McAuliffe, was watching television in the town library where he had just completed a staff meeting.

"When we saw the explosion, nobody said a word," Smith said, adding that he and others thought "maybe it was the camera angle" that made the fire look so ominous. When NASA announced what had happened, there was only disbelief and silence.

"It's hard to imagine it happening . . . . You almost avoid thinking about it," Smith said.

A few blocks away in the state Capitol, Gov. John H. Sununu (R) had joined a small group of reporters to watch the liftoff in the large meeting room where he usually sits with his executive council.

"Nobody said anything immediately except 'Oh my God.' It was obvious we were witnessing a tragedy," Sununu spokesman Frank Haley said later.

State Rep. William F. Kitter was with his appropriations committee when his clerk entered the room and said, "You'll never believe what's happened. There's been an explosion."

The legislature adjourned for the day.

"Oh, they are sick, sick," said Kitter who was watching a television set up in a hallway outside the press room.

Foley said classes at Concord High were canceled today and Wednesday because "the event of today destroyed anybody's ability to learn and any teacher's ability to teach. It's as simple as that."

But he said the catastrophe that ended McAuliffe's voyage and her life should not dampen the sense of adventure and excitement that she inspired in her students.

McAuliffe, Foley said, had told them to "reach for the stars" -- and those words are even more important now.

"Christa would want them to believe that," Foley said.

On the lawn outside the school where she taught since 1982, there is a stone marker, placed in memory of a teacher killed in a car accident long ago. It seems to capture the sense of pride that the city had in McAuliffe. It is engraved with a quote from Shakespeare:

"I love the name of honor more than I fear death.