SAN FRANCISCO — Perched on Alcatraz Island, California’s first-ever lighthouse has beamed welcomes and a sense of direction for 161 years to gold miners, clipper ships, oil tankers, nuclear aircraft carriers and cruise ships.

Now a campaign to rehabilitate and eventually open the working lighthouse to the public for the first time is being planned.

The National Park Service, Coast Guard, the United States Lighthouse Society and the Lands’ End clothing company jointly announced Monday the first step toward restoring the lighthouse, often overlooked in the shadow of the famous federal penitentiary around it.

Lighthouse backers commissioned a $25,000 architectural study to determine the scope and cost of the work — laying the groundwork for a major fundraising campaign to pay for it.

History buffs say securing the future of the lighthouse will enhance public appreciation of the island where the beacon was built long before the prison known as “The Rock.”

“Most people only know of Alcatraz because of the prison, but it has a rich maritime and lighthouse service history,” said Jeff Gales, executive director of the United States Lighthouse Society. “This lighthouse has stood guard while California’s development happened right around it.”

The lighthouse opened in 1854 and beamed on as the rest of the island transitioned from Army fort to federal penitentiary to federal park.

The extent of the necessary structural repairs is unknown, as is the cost of repairing the damage caused by a fire during an occupation of the island by Native American activists in 1970. That fire burned the lighthouse keeper’s house to the ground.

Seattle architect Gene Grulich will prepare a detailed historical structure report on the condition and rehabilitation needs of the 95-foot-tall reinforced concrete structure.

Rehabilitation is the first priority, but the lighthouse society says it hopes to see the lighthouse opened to public visitors at some time.

Now the lighthouse is closed except for special guided tours, like Monday’s tour, when a small group of media and dignitaries squeezed up the spiral staircase leading to the small lantern room overlooking San Francisco Bay.

Walking the 123 steep, narrow stairs to the top can leave visitors a little queasy. The views, however, of ships, bridges, pelicans, San Francisco skyscrapers and the vast expanse of blue bay waters are breathtaking.

Providing public access to such a cramped part of the popular park would be a challenge, but the National Park Service is willing to look at options, said Marcus Koenen, the Alcatraz site supervisor with the park service.

“We’re discussing it,” he said. “The tight space is the challenge. Look, we have 5,000 people coming to the island just today.”

Lands’ End is footing the bill for the architectural study.

“We want to save the beacon and make sure it is safe and available for future generations,” said Federica Marchionni, Lands’ End chief executive officer. “This is the oldest lighthouse in California. It is the most iconic lighthouse.”

Lands’ End, she said, was founded by Gary Comer, a sailor and world traveler who appreciated how lighthouses captured people’s imagination as a symbol of safe harbor.

The light from the Alcatraz lighthouse flashes every five seconds and can be seen 20 nautical miles away.

Despite modern ship navigators’ reliance on GPS and other technology, the automated lighthouse beam from Alcatraz is an important aid to mariners, said Coast Guard Capt. Bill Drelling.

“There is no substitute for a visual marker,” Drelling said, “especially on a foggy day.”

Contact Denis Cuff at 925-943-8267. Follow him at Twitter.com/deniscuff.