A pair of wildfires threatens an Arizona observatory partially owned by the University.

The blaze is approaching the Large Binocular Telescope, a $110 million facility situated on Mount Graham in Safford, Ariz. The facility – planned to be partially completed late this year – will be used by researchers around the world, including those at the University.

Firefighters are combating the fires, which lightning sparked about two weeks ago. The fires have spread throughout nearly 16,000 acres of land.

Workers have contained approximately 10 percent of the fire, at a cost of nearly $3 million, said University astronomy professor Chick Woodward.

“It’s basically still out of control,” he said.

Nearly 800 firefighters are operating on the northern side of Mount Graham, said Peter Wehinger, University of Arizona astronomer and staff development officer. The Large Binocular Telescope shares the mountain with two other observatories.

Eighteen teams of 20 workers – called hotshot firefighters – are extinguishing embers to prevent them from blowing to other areas, he said. Others are constructing a firebreak along the mountain.

Overhead, eight helicopters and four cargo planes are dropping flame retardant – a mixture of water, moisture-retaining clay and red dye – on the remaining forest.

Wind direction will partially determine the success of the firefighters’ efforts, Wehinger said. On Tuesday, winds were blowing from the south, going away from the observatory.

“The prevailing winds are in our favor,” Wehinger said. “But we’re not out of the woods yet.”

Weather and environmental conditions have aided the fire’s strength, Wehinger said. The area has suffered from a drought for more than six years. In addition, beetles have stripped the trees of their bark, increasing the wood’s dryness.

“The timber in the area is extremely dry,” Woodward said. “It’s drier than you would buy at Home Depot, and that’s dried in a kiln.”

The first rains of the monsoon season, which typically begins in early July, should extinguish the flames, said Bruce Walsh, University of Arizona ecology professor.

Walsh said the population of red squirrels, a species unique to Mount Graham, could be affected by the fires. Approximately 100 to 300 red squirrels live on Mount Graham.

Observatory officials sealed air vents, filled nearby tanks with water and initiated the building’s outdoor sprinkler system to prepare the facility for the blaze.

Still, Woodward said he worried that smoke or excessive heat could damage some equipment.

He noted that the building’s roof is a dome made of aluminum, which melts at certain temperatures.

Even if the fires leave the observatory and its equipment unscathed, some reconstruction will be necessary, Woodward said. For instance, roads and telecommunications destroyed during the blaze will have to be replaced.

The fires aren’t the first near a University observatory in Arizona. Last year, two wildfires threatened the Mount Lemmon Observing Facility, which the University has owned since 1970.

Flames came within several hundred feet of the observatory, but winds prevented them from reaching the building, Woodward said. But the facility suffered some damage and still smells of smoke, he said.

University astronomy professor Leonard Kuhi called the Large Binocular Telescope “the biggest thing to happen to the department in many years.”

In 2002, the University used a $5 million gift to gain partial use of the facility.

Woodward, Kuhi and other University astronomers receive frequent updates on the fires via an e-mail list sent by the University of Arizona, which operates the facility.

“We’re worried, because it’s such an important thing for our department,” Kuhi said. “Of course we’re concerned, but there’s very little we can do from here.”