CEDAR RAPIDS — The Sugar Plum Fairy is going to fall flat on her face, and “Hedwig’s Theme” from “Harry Potter” will lose its magic unless Orchestra Iowa raises enough money to buy a new celesta.

In the 1890s, when the Russian composer Tchaikovsky was preparing to write the music for the ballet that would become his holiday classic, “The Nutcracker,” he encountered a brand-new instrument: the ...