Late Sunday night, streetlamps cast an eerie glow on the sidewalk outside Christ Church of New Haven. Inside, the church is a murky cavern. A burst of candles at the altar casts just enough light to reveal more than 100 bowed heads robed in darkness and incense.

They listen, and the hallowed walls begin to sing.

For half an hour every Sunday at 10 p.m., Christ Church doubles as a medieval monastery, drawing flocks of New Haven residents and Yale students in search of a moment of spirituality, tranquility or just beautiful music. The 30-minute service, sung by a church choir comprising mostly Yale students, features sacred choral music dating from before the 18th century.

“It’s something otherworldly,” said Robert Lehman, organist and choir master for the Episcopalian church. “The experience you get by coming here is not something you get by turning on the radio.”

Students who attend Compline, the nighttime service, come from a myriad of spiritual backgrounds, including Judaism and atheism. Many simply seek a meditative moment before the week begins.

“I lose complete track of time — which is rare for me,” Elliott Huntsman ’02 said after last Sunday’s service. “Every time I come out I see things differently. I come out and it gives me a whole load of perspective.”

Huntsman said he is neither religious nor atheist, but comes for a half hour of serenity and to support friends who sing with the choir, which is hidden from the audience’s view in an upper gallery.

Lehman praised the diversity of the Sunday night congregation.

“Our job as a religious institution is to provide some sort of sacred sanctuary for people who are looking for something, and whatever they’re seeking, they’re finding here,” Lehman said. “The church provides a spiritual experience, and whether they realize it or not, that’s what they’re getting — on some level. There are as many different spiritual experiences as there are people sitting in the pews.”

Christ Church, located at the intersection of Broadway and Elm streets, has been offering Compline service since last spring in an effort to capitalize on its convenient location and attract more students.

Lehman said the church took its cue from the extraordinarily popular Compline services in Seattle that attracted nearby students from the University of Washington.

About 20 people attended the first service last spring. Now, the number has surged to an average of 100 each week.

The church placed ads for the service in the Yale Daily News, but Lehman attributes the popularity of Compline to word of mouth.

Compline comes with a high price-tag for the church, Lehman said. Its yearly budget of $30,000 covers the salaries of Lehman and the choir, and approximately 100 fast-burning candles per service, among other costs. Lehman said the rector completely supports continuing the services, but the vestry, the congregation’s decision-making body, has the final say.

Compline service has also become a meeting point for campus groups. Choir member Kendra Mack ’01 said she noticed secret societies gathering at services.

“It has that mysterious aura that secret societies aspire to,” Mack said.

The Duke’s Men also paid a visit, and the group’s director told them to listen to the choir as a model for music-making, Mack added.

At the end of each service, the only cue for people to leave is the choir’s silence. An intoxicating, ambrosial incense continues to envelope the pews as it whirls its way toward the vaulted ceiling.

The sexton of the church mixes the incense with a recipe that Lehman said the sexton “guards like you wouldn’t believe.”