Admission prices at the Carnegie Museums of Natural History and Art will go up as much as 80 percent in November, largely because of costs associated with an expanded dinosaur hall.

Entrance fees to the conjoined Oakland facilities will be raised $5 across the board, starting Nov. 21 for the opening of "Dinosaurs in Their Time," the natural history museum's redone dinosaur fossil hall, which will more than triple in size as a result of a $36 million renovation.

Tickets are going up from $10 to $15 for adults, $7 to $12 for seniors and students, and $6 to $11 for children 3 to 18. Carnegie museums membership fees will not increase.

The three-story dinosaur hall -- placed in a former courtyard in the rear of the museum building-- will house what is believed to be the world's third-largest collection of dinosaur bones, many of them purchased by Andrew Carnegie himself.

The higher fees will help pay operating costs that will expand with the much larger dinosaur hall, said David A. Smith, the natural history museum's acting co-director.

"There are just some big, big cost increases because of this hall. Additional maintenance, additional utilities, additional security, extended hours -- a lot of things we're trying to do for the public," Mr. Smith said. "Think about it -- 15 bucks gives you admission to two museums."

Mr. Smith said he could not estimate how much revenue will be generated by the higher charges, which will put admissions to the Carnegie Museum of Natural History on a par with those of the American Museum of Natural History in New York.

Similar museums in Chicago and Philadelphia charge adults $12 and $10, respectively, while the Cincinnati Museum Center, which covers seven cultural sites including a natural history museum, charges $10.25 to visit two of the sites.

Last year's paid attendance to the Oakland museums, which does not include visits from 22,000-member households whose fees will not increase, was 165,000. Next year, attendance is expected to spike by 40 percent, or 66,200, after the dinosaur hall opens -- a figure that, if all pay the extra $5, could generate an additional $1.1 million.

Carnegie Museums of Pittsburgh President David Hillenbrand and the museums board approved the fee increase after it was requested by Mr. Smith and Carnegie Museum of Art Director Richard Armstrong. Mr. Armstrong could not be reached yesterday.

Mr. Smith said museum officials set the prices after studying fees at similar cultural institutions around the area, and were not worried that a price increase would hurt attendance.

"We looked around the marketplace and we saw what it costs to go to Phipps, to the history center, to Kennywood, to Idlewild. Part of this is education, but we're also in the entertainment business. We tried to nestle in there, in an area we thought was pretty comfortable," he said.

With membership prices remaining stable, the admission fee increase may boost interest in memberships for the four Carnegie Museums of Pittsburgh, which also include the Carnegie Science Center and The Andy Warhol Museum. But that was not a driving factor in the decision to raise fees for the natural history and art museums, Mr. Smith said.

The Carnegie Museum of Natural History, one of the largest natural history museums in the country, closed its dinosaur hall in 2005 so that it could expand it from 5,000 to 18,600 square feet. Re-dubbed "Dinosaurs in Their Time," the new exhibition space will feature skeletons in scientifically accurate active poses, surrounded by period animals and plants.

"Yes, we raised prices $5, but people from around Western Pennsylvania and the country who come to this, they're going to get their money's worth," Mr. Smith said.

Funding sources for the $36 million expansion included $15 million from state government, $5 million from the Eden Hall Foundation, $4 million from the Howard Heinz Endowment, $3 million from the Richard King Mellon Foundation and other private gifts.

The museum also is asking private donors to sponsor dinosaur bones -- it will take that "adopt-a-bone" effort to the public in October -- and all those who purchased the 100 "DinoMite Days" dinosaurs as part of a public art initiative in 2003 to put them on display this fall to help generate buzz for the dinosaur hall reopening.

The first phase of the hall will open to members for three days before opening to the public Nov. 21. A second phase, featuring two fighting T. rexes, is to open in the spring, perhaps in May.

From Nov. 21 through Nov. 30 -- with the exception of Thanksgiving Day, Nov. 22 -- the Carnegie Museums of Art and Natural History will stay open until 8 p.m. to handle the increased crowds. They open at 10 a.m. Tuesdays through Saturdays and at noon Sundays. Tickets, at the higher price, are available online at www.carnegieonline.org/cmnh.