Stephen Tharp, the guest organist scheduled to perform a concert Tuesday as part of the Friends of the Kotzschmar Organ’s summer concert series, has had to cancel his appearance due to illness.

Portland’s municipal organist, Ray Cornils, will replace Tharp. The concert is scheduled for 7:30 p.m., with a pre-concert talk beginning at 6:30 p.m., at Portland’s Merrill Auditorium. Tickets are $17; free for youth 12 and younger. Go to for tickets.