If you can pick out Atlanta's nighttime skyline from a lineup with other big cities, thank Lee Cronan.

A principal engineer and lighting designer at Georgia Power, Cronan helped light 51 Atlanta skyscrapers to give the world's cameras something to focus on when the 1996 Olympics came to town.

Mikki K. Harris/AJC (ENLARGE)

Lee Cronan, Principal Engineer for Georgia Power, is proud of Atlanta's skyline but sympathetic with the event that will darken in this weekend.

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He designed the waterfall effect on the stair-stepped face of Georgia-Pacific's headquarters at 133 Peachtree Street and the flying-saucer-taking-off look for the Hyatt Regency Atlanta at 265 Peachtree Street.

"I spent many a day sitting here looking at photographs of the buildings, trying to determine what can we do to make the building unique," Cronan said in his office, a nondescript, one story Georgia Power outpost on Ralph McGill Boulevard about a mile east of the company's shiny black headquarters.

"You want to make that building become its own individual."

So imagine how he felt when an international environmental organization asked for his help to turn 'em all off from 8 to 9 tonight in the spirit of combating global warming.

"All those lit buildings are my babies," Cronan said. But he's sympathetic with Earth Hour's energy conservation goal. More than 200 cities, including 50 in the U.S., are participating in the event organized by the World Wildlife Fund. Atlanta is one of four flagship American cities, representing the East Coast.

"They're trying to make people aware of being good stewards of our natural resources," Cronan said. "I don't want to be wasteful. We light things because there's a reason to do so."

More than 400 buildings across the metro region have agreed to participate, organizers said Friday at a rally in Atlanta City Hall. They include Atlanta's iconic buildings, from one of the newest, the Georgia Aquarium, to the tallest, the Bank of America Tower. Some restaurants have agreed to light candles for their diners during that hour, including Canoe in Vinings and Einstein's in Midtown.

Organizers are encouraging people to participate by turning off non-essential lights inside their homes.

The difference in the city's skyline won't be vivid until about 8:30 p.m., after the sky completely darkens. Dusk ends at 8:21 p.m., according to the U.S. Naval Observatory's Astronomical Applications Department.

Atlanta's organizing team hopes to reduce the city's power consumption by 5 percent compared to the same time on another Saturday night, Cronan said.

A.J. Robinson, president of Central Atlanta Progress, the civic group that organized the "Light Up Atlanta" street parties in the 1980s to coax people back downtown and rallied businesses to light the streets and skyscrapers in the early 1990s, said now building owners are starting to think about ways to save energy.

"This particular exercise is a symbolic way to show solidarity with the rest of the globe," Robinson said. "It's showing what you can do in one hour of saving energy around the world."

But Robinson doesn't think Atlanta will go back to the dark nights of yesteryear, not even to reduce the city's carbon footprint.

"There's all kinds of ways to save energy in buildings" without turning off exterior lights, he said. The lit skyline "gives people an image of Atlanta that's growing and a place of opportunity. . . It's inspiring."

Cronan said accent lights used on the building's exterior are more efficient than even the squiggly compact fluorescent bulbs people can use in their homes. Exterior lights account for less than half a percent of a building's energy use, he said.

Like Robinson, he has a long list on the pro side of the column to recommend lighting Atlanta's skyline. Prime among them is making the city feel safer and more attractive to visitors.

"We don't have the Eiffel Tower. We don't have a prominent shoreline. We don't have a Space Needle. What we do have is the largest main street in the world," Cronan said, referring to Peachtree Street.

Stephen Smith, executive director of the Southern Alliance for Clean Energy, an environmental organization promoting alternative energy sources, said raising awareness about global warming and saving energy is always good.

"It's quite amazing how much energy we waste in this country and across the world," Smith said.

"There's a danger, though, if anyone thinks turning off the lights for one hour is in any way going to be a serious solution to the problem. ...At some point we've got to get on with the business of passing federal legislation that sets a price for carbon. ...That's what will solve the problem."