No classes on full or new moons.  
Times given are specific to Santa Cruz:

2021
January 12 - Tuesday - New at 9:00 PM 
January 28 - Thursday - Full at 11:16 AM
February 11 - Thursday - New at 11:05 AM
February 27 - Saturday - Full at 12:17 AM
March 13 - Saturday - New at 2:21 AM
March 28 - Sunday - Full at 11:48 AM
April 11 - Sunday - New at 7:30 PM
April 26 - Monday - Full at 8:31 PM
May 11 - Tuesday - New at 11:59 AM
May 26 - Wednesday - Full at 4:13 AM
June 10 - Thursday - New at 3:52 AM
June 24 - Thursday - Full at 11:39 AM
July 9 - Friday - New at 6:16 PM
July 23 - Friday - Full at 7:36 PM
August 8 - Sunday - New at 6:50 AM
August 22 - Sunday - Full at 5:01 AM 
September 6 - Monday - New at 5:51 PM
September 20 - Monday - Full at 4:54 PM
October 6 - Wednesday - New at 4:05 AM
October 20 - Wednesday - Full at 7:56 AM
November 4 - Thursday - New at 2:14 PM
November 19 - Friday - Full at 12:57 AM
December 3 - Friday - New at 11:43 PM
December 18 - Saturday - Full at 8:35 PM