Maury Povich, the host of "Panorama" and the anchor of Channel 5's 10 p.m. news, will leave both Washington shows for 10 weeks this summer to host a New York late-night news magazine show.

The new show, which begins in late July and runs until Joan Rivers makes her debut in October, will air only in New York as an experiment. It will occupy the 11:30 p.m. time slot that Rivers will take over on the Fox network, which recently bought Channel 5.

WTTG News Director Betty Endicott said the station was not planning to hire anyone new to fill in for Povich. "We'll use our staff people," she said.

Povich, who has worked in San Francisco, Los Angeles, Chicago, Philadelphia and Washington, said, "As somebody once said of me, I'm going network, city by city."

Expectations for the new show, which does not yet have a title, are modest. "We're going to be running against Carson and 'Nightline,' so even a little success could mean the start of something," Povich said.

With Fox Broadcasting Co., Rupert Murdoch has been trying to build a "fourth network." He made a big splash recently when he lured Rivers with a huge contract to compete with her erstwhile mentor, Johnny Carson. Fox has stations in Washington, New York, Dallas, Houston, Chicago and Los Angeles. This is the first indication that Fox may spend some of its resources on news.

After leaving the set of "The 10 O'Clock News" last Thursday, a Fox executive called Povich to come to New York and meet with Murdoch the next morning. "I took the first plane out of Washington," Povich said. Friday morning, Murdoch told Povich the new program would feature three or four segments with a predominantly local emphasis.

"They said it will have a hard edge to it," Povich said, "but we'll have features, too. When you talk to these people, you ask, 'Will it be like 'Nightline?' and they say, 'No.' And then you ask, 'Is it going to be like 'Entertainment Tonight?' And they say, 'No.' It's hard to tell. They did say it would be very New Yorky. Of course, if you get a Chernobyl, I don't think you ignore it."

Fox has yet to hire a producer or a team of reporters for the show. "We've got to get this thing together in a hurry," Povich said.

Povich's wife, NBC News reporter Connie Chung, said she is enchanted with the turn of events. As one of the hosts of the new Washington-based series "1986," which premieres tomorrow, Chung said, "I was getting ready to shlep all my clothes from our apartment in New York to our place in Washington. Now I guess I won't do that.

"We were also set to compete against each other because Maury's on the news at 10, and '1986' is on then, too. So this spares us that. This is too hysterically funny."

Of his future and that of the new show, Povich said: "If it fails, it fails. If it succeeds, does decently in the ratings, they'll see if they can find a time slot for it.

"As for me, I expect to come back to Washington when the 10-week period is up. We'll see from there."

Povich's contract with WTTG runs out at the end of the year. His summer job has not increased or decreased his paycheck. "It's very strange," Povich said. "It hasn't come up. But who's had time?"

Murdoch, whose reputation in the U.S. news business is best exemplified by the lurid headlines on the New York Post, is hoping to make Fox competitive with CBS, NBC and ABC. But Povich said, "As far as I know, on a day-to-day basis, Murdoch doesn't want anything to do with this show."