NEW YORK (AP) – Now that Katie Couric is making the move from dawn to dusk, her legacy – and the future of CBS News – depends on the audience. And according to a new poll, that audience prefers to see her in the morning.

Asked if they would rather see Couric in her longtime role as “Today” host or as the first woman to anchor a network weekday evening newscast on her own, 49 percent favored the morning and 29 percent said evening, according to a poll conducted this week by The Associated Press and TV Guide.

After 15 years as morning television’s queen, Couric confirmed Wednesday that she is leaving NBC’s “Today” show to become anchor and managing editor of the “CBS Evening News” this fall. Her audience at “Today” is about 6 million viewers; “CBS Evening News” has about 7.5 million.

The woman who dressed in Marilyn Monroe and SpongeBob SquarePants outfits on Halloween and gave viewers a tour of her colon will take the position once held by the iconic Walter Cronkite and the ousted Dan Rather.

But claims that Couric lacks the “gravitas” for the job are “thinly disguised sexism,” said news consultant Andrew Tyndall.

Few questioned Tom Brokaw when he switched from a “Today” host in the 1970s to become NBC top anchor. At ABC, Charles Gibson frequently did the morning and evening newscasts on the same day this past year during the late Peter Jennings’ illness.

“I think her strengths” – three hours a day of live broadcasting covering a wide swath of topics – “will evolve and magnify to fit the task,” said Frank Sesno, a journalism professor at George Mason University and special CNN correspondent.

“Sometimes I think change is a good thing,” Couric said on “Today.” “Although it may be terrifying to get out of your comfort zone, it’s very exciting to start a new chapter in your life.”

NBC was moving swiftly to replace her. “The View” co-host Meredith Vieira, a former “60 Minutes” correspondent, was close Wednesday to accepting NBC’s offer to join Matt Lauer on “Today” starting this fall, according to a person familiar with the negotiations who spoke on condition of anonymity because a deal had not been completed.

Couric, 49, grew up in journalism backstage at CNN, then joined NBC as a Pentagon reporter in 1989. In April 1991, she was installed next to Bryant Gumbel to wipe away the stain of Deborah Norville’s disastrously brief tenure.

It was a master stroke that earned hundreds of millions for NBC and its parent, General Electric Corp. Couric, paired with Lauer since 1997, will leave next month as the longest-serving “Today” host in the show’s 54-year history. The show is in the 11th year of an unprecedented ratings winning streak.

Her success helped pave the career rise of Jeff Zucker, once Couric’s executive producer and now, as CEO of the NBC Universal Television Group, responsible for overseeing a smooth transition at “Today.”

“There comes a time for everyone, when new challenges become hard to resist, and I fully understand that,” Zucker said. “I couldn’t be happier for Katie.”

Couric turned down an offer of about $20 million a year to stay at NBC in order to take CBS’ five-year deal at near her current salary of about $15 million, according to people close to negotiations who spoke on condition of anonymity because networks do not speak publicly about salaries. She’s also agreed to do “60 Minutes” stories and prime-time specials for CBS. The lure of making history in the evening – and an end to pre-dawn wake-up calls – proved irresistible.

Couric’s morning job required her to interview everyone from presidents to preening celebrities to a runaway bride. Some critics have questioned whether those skills translate well to a job that primarily involves reading news headlines and presiding when big news strikes.

“If we have another (terrorist) attack or hurricane and need life-saving information, I think her image is that of more fluff than fact and that’s going to have an impact,” said Jeff Alan, author of “Anchoring America: The Changing Face of Network News.”

She seemed far from her hard news roots last November while serving as host for NBC’s Thanksgiving Day parade coverage and missing the story of a spectator hurt by a falling street lamp – a development CBS aggressively pursued.

It hasn’t helped that the morning show balance has tipped to the less serious, said Charlotte Grimes, a journalism professor at Syracuse University. She said the new anchor needs to ditch the fashion consultants and crafters of the 172 hairstyles that Couric joked about on Wednesday’s “Today” show.

“I think she does have the background but she’s going to have to overcome the most recent memories of her,” she said.

Barbara Fleming was among the poll respondents who preferred Couric in the morning. Although Couric is good at interviews, “mostly I see her in an entertainment role,” said Fleming, 62, of Columbus, Ohio.

Despite the public’s initial wariness, the poll suggests that Couric is making the transition at a good time. More than half of those polled, 55 percent, have a favorable view of Couric. That’s comparable to the favorable views toward NBC anchor Brian Williams and interim CBS anchor Bob Schieffer, while higher than ABC’s Elizabeth Vargas.

Only veteran broadcaster Diane Sawyer of ABC’s “Good Morning America” received higher marks than Couric, with more than seven in 10 viewing her favorably. About half of the respondents say they are likely to tune in and see Couric in her new role, but the poll suggested the immediate impact on steady viewership may be limited.

The AP-TV Guide poll of 615 adults was conducted by Ipsos on Monday and Tuesday. It has a margin of sampling error of plus or minus 4 percentage points.

On her first “Today” broadcast as Gumbel’s co-anchor on April 5, 1991 – replayed on its 15th anniversary Wednesday as she announced her imminent departure – Couric was identified as “Katherine.” The more formal first name was swiftly changed.

Now that she’s got the big CBS job, should she return to Katherine?

“No way,” Tyndall said. “Did they ever call Brokaw ‘Thomas Brokaw?’ You don’t go back. It would seem like you’re disavowing the last 15 years of your life.”

As her “Today” tenure lengthened, Couric also gained detractors whose view was most infamously stated by Alessandra Stanley of The New York Times last year: “America’s girl next door has morphed into the mercurial diva down the hall. At the first sound of her peremptory voice and clickety stiletto heels, people dart behind doors and douse the lights.”

But Tyndall argued that Couric had achieved an impossibly high standard of popularity that couldn’t be sustained. Couric had the last laugh when “Today” rebounded strongly from ABC’s challenge in the past year.

CBS clearly hopes she’s a star who can give a bright new face to its last-place news division, attract younger viewers and inject life into a hidebound TV format.

The network also hopes Couric encourages other news stars to come to CBS – the same formula that CBS Corp. President Leslie Moonves used to revive the entertainment division and Sean McManus did for CBS Sports.

Couric leaves a show that is the unquestioned leader in its field, and the most profitable news program on TV.

Ironically, with Schieffer filling in for the past year, the “CBS Evening News” is growing its audience – unlike NBC and ABC.

The conversational style that Schieffer has brought to the broadcast, where he frequently questions correspondents on-air about their stories, will continue with Couric. A new set, new graphics and a more contemporary style will also be fashioned around her in time for a September debut, the network said.

“I couldn’t be happier,” said Schieffer, whose future role – if any – in the broadcast was unclear Wednesday. “Katie and I have been friends for years. She’s going to be a terrific addition to CBS News. I think we’re going to love Katie and I think Katie’s going to love us.”

The move is also an expensive gamble. Nearly a decade ago Gumbel made a highly publicized switch from “Today” to a prime-time newsmagazine at CBS. It proved a flop, and Gumbel moved back to the morning, but could never get CBS out of third place.

Still, it’s a coup for Moonves, who targeted Couric from the time Rather was forced out more than a year ago. It’s been in the works for several months, but negotiations heated up during the past few weeks, when NBC waived a contractual provision that prevented Couric from negotiating with another network until May.

Moonves also scores a major victory in his corporate rivalry with Zucker.

Couric is expected to stay at “Today” until the end of May.

AP-ES-04-05-06 1712EDT