Washington Cathedral's annual open house, to be celebrated Saturday from 10 a.m. to 5 p.m., launches a year-long celebration of the Episcopal cathedral's 75th year.

Church leaders, taking their cue from the original vision for the cathedral as "a house of prayer for all people," have planned a series of events throughout the year around the theme of reconciliation.

Saturday's open house will feature demonstrations by cathedral artisans; music of bells, voices, organs and bagpipes; puppet shows, tours and a climb to the top of the central tower for a view of the city from its highest vantage point.

The climax of the day, beginning at 4 p.m., will be the blessing of an 8-foot stone Celtic cross and its placement atop the west nave, completin the marking of the four compass points on the cruciform-shaped cathedral.

As part of its year long reconciliation theme, the cathedral will hold a symposium on Veteran's Day, Nov. 11, on "The Vietnam War -- Unfinished Business."

Throughout December, a special Advent series will feature such well-known clergy as evangelist Billy Graham, Episcopal Presiding Bishop John Maury Allin and Bishop John M. BurgessM the first black bishop in the Episcopal Church, who once served as a canon at the cathedral.

An unprecedented exchange of cathedrals between Bishop John T. Walker and Roman Catholic Archbishop James A. Hickey will take place in January. While Hickey's predecessor, Cardinal William W. Baum, has spoken from the Episopal cathedral pulpit, Walker never before has been invited to preach at St. Matthew's Roman Catholic Cathedral here.

In January, Dr. Martin Luther King Jr. will be honored at a service in which his widow, coretta Scott King, will take part. The late civil rights leader preached at the cathedral on the Sunay before his assassination. The cathedral has commissioned a statue of Dr. King.

There is no admission fee for Saturday's open house. Visitors are invited to picnic on the grounds.