By Daniel Lovering

CAMBRIDGE, Mass. Feb 17 (Reuters) - Thousands of items that belonged to a longtime aide of President John F. Kennedy were headed for the auction block on Sunday in the 50th anniversary year of his assassination.

The late president's Air Force One bomber jacket, letters, photographs and other items had been tucked away in drawers and file cabinets at the home of David Powers, who died in 1998, said Dan Meader, auction appraiser at John McInnis Auctioneers. They were discovered in recent years by relatives as they prepared the Arlington, Massachusetts, residence for sale, he said.

Powers was close to the president throughout his political career, from 1946 until his assassination in 1963. He remained close to the Kennedy family and became curator of the John F. Kennedy Presidential Library and Museum in Boston before retiring in 1994.

The auction will include personal effects that Powers kept throughout his lifetime and reflect his years of shared history with Kennedy and his family. Among them are dozens of letters from former first lady Jackie Kennedy and books inscribed by the president.

"The amazing thing about this whole thing is that it shows the personal connection," Meader said. "This is stuff that's true, it's pure, it's right from the family home ... right from the president's best friend."

Also among the items to be sold was a schedule kept by Powers that documented in minute detail his last two days with Kennedy in San Antonio and Dallas, Texas, before the Nov. 22, 1963, assassination.

Powers traveled with Kennedy, riding in motorcades, monitoring the reaction of crowds and informing the president of what his constituents wanted, Meader said.

"He was basically the eyes and ears of the American public," he said. "Dave was the pulse of the nation."

Kennedy's Air Force One leather bomber jacket was expected to fetch $20,000 to $40,000 or more. A pen he used to sign an interdiction order during the Cuban missile crisis will also be up for auction.

The entire collection was expected to sell for as much as $800,000, Buyers from around the world were expected to bid throughout the day on Sunday, Meader said.

(Editing by Barbara Goldberg and Maureen Bavdek)

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  • Birthday Card From John Jr.

    <strong>Bid estimate:</strong> $2,500 - $5,000 Birthday card from John, jr. to his father on his 46th birthday, signed "John xxooxxo"

  • Jackie, Ethel and J.F.K. Photograph - 1954

    <strong>Bid estimate:</strong> $100 - $200 A mirror shot of Ethel, Jackie and JFK taken in 1954.

  • Air Force One Bomber Jacket

    <strong>Bid estimate:</strong> $20,000 - $40,000 This Air Force One leather Bomber Jacket belonged to and was worn by J.F.K. before being gifted Dave Powers in 1962 or 1963.

  • Medallion And Hour Glass

    <strong>Bid estimate: </strong> $100 - $200 J.F.K. bronze medallion with hour glass and White House calling card signed "All the best wishes John F. Kennedy."

  • Jackie And JFK Photo

    <strong>Bid estimate:</strong> $750 - $1,500 1953 wedding photo signed: "To Dave and Jo Powers with best wishes Jackie Kennedy."

  • Kennedy Family In Hyannis

    <strong>Bid estimate:</strong> $100 - $200 Photographs of J.F.K., Bobby, Eunice and Pat at the Kennedy family compound in Hyannis.

  • JFK In Top Hat

    <strong>Bid estimate:</strong> $100 - $200 J.F.K. with top hat at the 309th Harvard commencement ceremonies, 1960.

  • JFK With Eisenhower

    <strong>Bid estimate:</strong> $50 - $100 JFK with Dwight Eisenhower at Camp David in 1961.

  • J.F.K.'s Schedule During Assassination Trip

    <strong>Bid estimate:</strong> $2,000 - $5,000 An original working copy of the President's schedule during his trip to Dallas on November 21 and 22,1963, that ended in his assassination.

  • Elaine de Kooning Portrait

    <strong>Bid estimate:</strong> $5,000 - $10,000 Portrait of JFK by Elaine de Kooning, 1963.