TUCSON, Ariz. (AP) -- Crews battling a 20,000 wildfire in southeastern Arizona continued to build protection lines around the blaze Saturday and were prepared to conduct burnout operations to protect an observatory site if the need arises, officials said.
The Florida fire had moved into Madera Canyon, where a small number of homes were threatened, but crews completed a successful burnout operation and continued their efforts to protect the structures, said fire information officer Rick Hartigan.
The blaze was roughly a mile from the Fred Lawrence Whipple Observatory, where plans were made for burnout operations aimed at robbing the fire of forest fuels, Hartigan said.
''Right now, it's all preparation work,'' Hartigan said. ''There is no burnout in progress there.''
Burnout operations would begin near the observatory if the fire crosses certain trigger points.
The observatory has at least $100 million worth of telescopic equipment sitting 900 feet below Mount Hopkins' 8,550-foot summit. All residents and workers had been evacuated from both sites.
Madera Canyon is a favored hiking, picnicking and bird-watching area that has 30 homes and summer lodges.
By midday Saturday, the fire was 40 percent contained. There was no estimate for full containment of the fire, which started on July 7.
Burnout operations and the construction of protection lines continued Saturday on the west and south sides of the fire. More than 850 firefighters were assigned to the blaze.
