NEW YORK -- On a recent afternoon at Radio City Music Hall, a group of Rockettes were being examined with critical eyes.
The 36 dancers practiced one of their signature synchronized numbers, their long limbs seemingly in perfect symmetry. They moved like swans, chins up, arms graceful.
Dance captain Karen Keeler drilled them until the last few moments before another group took the stage. "A one, two, three, four, five, six, seven, eight, one, up two, a three and a four," she sang out.
Linda Haberman, director and choreographer of the annual "Radio City Christmas Spectacular," watched from the seats and asked Keeler’s opinion of this group of women. It wasn’t positive.
"They were just kind of taking it easy. Do you want me to continue?"
"We have, I think, six seconds," replied Haberman. "So if you can say it in six seconds, you can do it."
Keeler looked at her charges. "Do it all better," she told them.
Haberman laughed. "Details," she said.
The show, which opens today and runs through Dec. 30, marks the 85th anniversary of the "Christmas Spectacular" and Haberman is determined to put on a birthday party appropriate for this grand old lady. When one thinks of Christmas in New York, who doesn’t immediately imagine a line of crystal-bedecked women high-kicking it?
Haberman, who has been choreographing the show at Rocke feller Center since 2006, has managed to pull the 90-minute show into the Wii era, adding digital projections on LED screens, a 3-D section that requires special glasses and even sequence inspired by a computer game.
"I try to look at it with new eyes every year," she says. "It’s really important to honor our past. There are things that are part of the Rockettes’ rich history that I would never let go of. But I think it’s important to keep the Rockettes as entertainment relevant to our changing times."
It was Haberman who added a new favorite routine -- the Rockettes dancing on a double-decker tour bus. But there are some things she won’t mess with: the "Nutcracker" minisuite, the woozy fall of the wooden soldiers, the "Living Nativity" and "The 12 Days of Christmas" sequences. Haber man keeps those classics but is always tinkering.
"I never leave anything alone because I can always make it better," she says. "I don’t just leave something. Even if it’s been in the show for five years."
This year, in a nod to the an ni versary, the show will have a costume retrospective featuring Rockettes wearing some costumes they’ve worn through the decades.
The Rockettes have shrugged off Superstorm Sandy. Rehear sals were canceled for three days and vans had to pick up stranded dancers, but there will be no delays. "It’s like New York. Everyone’s pulling toge ther and working hard and we’ll get it done," Haberman says.
Haberman is an exacting task master. Calm, but steely. A graduate of the School of Am er i can Ballet, she became the youngest cast member in Bob Fosse’s "Dancin’." Precision is in her blood.
"I’m tough with the ladies," she says. "But I think they re spect me and I think they re spect the work they’re doing and that’s really the key."
Haberman, who will start work on the next show in Jan u ary, rehearses two casts at the same time -- a total of 152 people -- who alternate playing the punishing schedule of five shows a day, six days a week. There are 80 Rockettes since each show needs 36 ladies and four standbys.
"As a choreographer, you’re always playing with formations, especially with the Rockettes. Thirty-six is a great number be cause you can divide it by two, you can divide it by three," she says. "Different choreographers like different numbers. I love 36. It becomes a math project."
The Rockettes, some 500 applied last spring, come from different backgrounds -- some are Broadway dancers, some are Pilates instructors -- but they must stand between 5-foot-5 and 5-foot-101Ž2. That’s simply due to Haberman’s attempt to arrange her dancers to make a "pleasing effect."
"I look at the line now compared with when I started in the ‘90s and they’ve just changed. These women train like crazy, they are all so strong and so tough and such good dancers -- it’s great," she says. "Now I can choreograph anything. I’m not limited."