If you go Greater Boulder Youth Orchestras’ outreach concert with Boulder Philharmonic: 2 p.m. Sunday, April 27, Mountain Range High School, 12500 Huron Street, Denver, $5, free for students and music teachers; 720-891-2259 or greaterboulderyo.org CU Symphony Orchestra’s “Planets” Concert: 7:30 p.m. Tuesday, April 29; Macky Auditorium, University of Colorado campus, $10-$20; 303-492-8008 or cupresents.org. Boulder Bach Festival Artist Recital featuring Zachary Carrettin, Lina Bahn and David Korevaar: 7:30 p.m. Friday, May 2; First Congregational Church, 1128 Pine St., $30; 303-776-9666 or boulderbachfestival.org. Greater Boulder Youth Orchestras’ full concert with concerto competition winners Allyson Stibbards and Adrian Emmett-Mattox: 2 p.m. May 4, Macky Auditorium; $15, free for music teachers; 720-891-2259 or greaterboulderyo.org

It’s an unusually rich week for big classical events in Boulder.

Tuesday at Macky Auditorium, the University Symphony Orchestra presents its much-anticipated interpretation of Gustav Holst’s beloved orchestral showpiece “The Planets.”

Music director Gary Lewis says it will be a great experience for his young musicians, with challenges for all players. Filmmaker Mark Hatch brings his video production of NASA imagery, which will be coordinated with the music. Former astronaut Joseph Tanner will provide narration between the movements, introducing each “planet” before its musical portrait is played.

The world premiere of “The Dutch Stonewall,” a 20-minute work for two pianos and string orchestra by CU composer Carter Pann, will open the program. Faculty pianists Alexandra Nguyen and Margaret MacDonald are featured.

“It’s a stunningly beautiful piece,” Lewis said. “And ‘The Planets’ will really be a unique, multisensory event.”

Friday at First Congregational Church, the Boulder Bach Festival closes its season with the much-anticipated artist recital featuring pianist David Korevaar and violinist Lina Bahn, both CU faculty members. Music director Zachary Carrettin also will play on the program.

Carrettin compares the event to September’s season-opening recital, which featured chamber music on period instruments. This recital includes solo works played on more modern instruments, including the grand piano and a violin with modern strings and a modern bow.

“I want to establish a dialogue about period instruments vs. modern instruments,” he said. “David Korevaar is a masterful interpreter of Bach on the modern piano, for instance.”

Bahn and Korevaar each will perform one of Bach’s partitas for solo violin and solo piano. Carrettin plays one of the solo cello suites transcribed for viola. Bahn and Korevaar then will join on a sonata for keyboard and violin.

“In a way, Bach’s instrumental music is more sacred than his church music,” Carrettin said. “It shows that Bach can come close to God with just musical tones and no words. It has a profound effect on the psyche.”

The Greater Boulder Youth Orchestras close their season with two events featuring the organization’s concerto competition winners. The first is at 2 p.m. today in an hour-long outreach concert with the Boulder Philharmonic Orchestra. It takes place at Mountain Range High School in northwest Denver and features violinist Allyson Stibbards, one of the two competition winners. Stibbards is a senior at Skyline High School in Longmont. The most advanced of the organization’s groups will play alongside Phil musicians.

A full season-finale concert takes place May 4 at Macky Auditorium.

“All four of our ensembles will play,” GBYO executive director Brian Jack said of the May 4 concert. “Our middle-level group will play ‘Spring’ from Vivaldi’s ‘Four Seasons’ with our competition winner, Adrian Emmett-Mattox.” Emmett-Mattox is an eighth-grader at Shining Mountain Waldorf School. That group also will play a movement from Franck’s D-minor symphony and a short piece by Haydn.

The wind ensemble plays the world premiere of “Variations on a Theme by Haydn” by Colorado composer Mark Arnett. And the advanced group repeats its program from today’s outreach concert, with Stibbards playing the last movement of Tchaikovsky’s Violin Concerto. The group will play three movements from Carl Reinecke’s Serenade for Strings.

Jack emphasized the importance of GBYO’s collaboration with other area classical organizations, including their first event with the Boulder Bach Festival this fall.

“We work with individuals from many orchestras,” he said, “and most of our mentors are CU students,” he said.

CU’s Gary Lewis is GYBO music director, but he is currently on leave. The concert will be conducted by CU band director Donald McKinney. GBYO is holding auditions for next season May 10 and May 12.