Here’s a handy organ accompaniment (PDF) in three different key signatures: MIDDLE, HIGH, and LOW. The Latin lyrics (“Silens Nox”) are courtesy of Father Valentine Young, OFM (d. 2020). The organ harmonies are very simple, yet beautiful. Those who desire such a thing may also download a Singer’s Version. For obvious reasons, the choir will ‘pick up’ this piece up with minimal rehearsal time. Here’s a live recording from Midnight Mass at Saint Vitus Parish: LIVE RECORDING.