A bleak, barren desert in the middle of New Mexico might seem an unlikely place for a full-scale, open-air opera house, and Santa Fe, though most definitely a city, is hardly regarded by most outsiders as a major arts center. So the very existence of Santa Fe Opera “represented a gamble that people from far away would come to regard Santa Fe as they already regarded England’s Glyndebourne, as a pilgrimage destination for opera. And the gamble has clearly paid off. The current 50th anniversary season of five operas, running in repertory until Aug. 26, is virtually sold out, with visitors from around the world.”