They were each Moscow born, were celebrated as child prodigies, attended that city’s School for Musically Gifted Children and later graduated with honors from the Tchaikovsky Conservatory of Music, won international music competitions, and went on to become principal musicians in the Bolshoi Theatre Orchesta, she as the harpist and he on the viola. Now Sergey Rakitchenkov and Olga Ortenberg-Rakitchenkov, both currently with the San Francisco Opera Orchestra, are joined by pianist Arkady Serper in a program of works by Handel, Bach, Bruch, Schubert and Spohr.