MOUNT DIABLO -- A historic beacon on top of one of the Bay Area's most prominent peaks will shine brighter and crisper on Pearl Harbor Day this Saturday after an extensive overhaul by volunteers.
Conservationists restored the 1928 beacon to keep it working for its once-a-year lighting on Dec. 7 to honor victims and survivors of the 1941 attack on Pearl Harbor. Lack of state maintenance and extreme mountain weather had threatened to extinguish the light.
Once the restoration began, however, volunteers also figured out how to brighten the rotating beam.
Crews moved the bulb slightly up and away from the focal point of the beacon mirror, directing the light to shine more brightly and directly at Bay Area cities. The beacon atop the 3,849-foot-peak initially pointed higher up because it was used as an aviation guide.
The restoration team also replaced a 1,000-watt bulb with a 1,500-watt one for the beacon lamp.
"There will be more people seeing the beacon more intensely than in the past," said Ron Brown, executive director of Save Mount Diablo, the group that spearheaded the restoration. "We think it makes sense to focus the beacon on the communities around the mountain."
The beacon will light up shortly before 5 p.m. Saturday following the annual Pearl Harbor memorial ceremony, which begins at 3:45 p.m. at the summit building at the top of Mt. Diablo State Park in central Contra Costa County.
Brown said he expects larger than normal crowds because of the media coverage of the $100,000, four-month restoration performed by volunteers in a Concord warehouse.
In one of their last chores, volunteers checked the light adjustments by stationing themselves at several places around the East Bay at night to monitor the beacon during a test.
Three Pearl Harbor survivors are scheduled to attend Saturday's ceremony and speak.
Pearl Harbor survivors strongly supported the restoration to keep the annual ceremony alive, said Wayne Korsinen, a retired teacher and honorary member of the Pearl Harbor Survivors Association.
"The future of the beacon was uncertain, but now the few survivors who are in their 80s or 90s know the beacon will survive at least another 80 years," Korsinen said.
Attendance at the beacon ceremony dwindled in the 1990s, but picked up after the Sept. 11, 2001, terrorist attacks that killed nearly 3,000 people.
Saturday's ceremony will be the first public event at the Mount Diablo summit building since its viewing deck was reopened last month after being closed for repairs for nearly a year.
The beacon was installed by Standard Oil Co. and remotely activated in 1928 by famed aviator Charles Lindbergh to help planes navigate. After the Japanese attack on Pearl Harbor in 1941, the beacon was turned off until relit in 1964.
Contact Denis Cuff at 925-943-8267. Follow him at Twitter.com/deniscuff.