The student musicians who make up the New York String Orchestra sacrifice their Christmas vacations to polish their musical skills. Tonight, one of them will get a belated Christmas present of $1,000 to compensate for that sacrifice. The decision will be announced by violinist-conductor Alexander (Sasha) Schneider and other consultants during tonight's performance in the Kennedy Center Concert Hall.

John Thacher, a patron of chamber music who died last February, left $10,000 in his will to Lily Guest, chairman of the Friends of the Kennedy Center, to benefit the arts. Guest has decided to take $1,000 each year and use it in a different way. Thacher, who was the director of the Dumbarton Oaks concert series and an avid music patron, hosted an annual dinner for the students who visit Washington as members of the New York String Orchestra. Guest decided that this year's installment of the $10,000 should go to one of the students.

Does the gift have any restrictions? Must it be spent on schooling? "Of course not. They may need shoes," she says, shrugging, "or a new coat."

The money is not reserved for musicians. "Next year it could go to a dancer, or an actor," says Guest. "But this year it will go to a student of Sasha's. Really, there are no strings attached."