Anyone interested in the juncture between ambient music and Americana would do well to take a quiet hour with Let the Moon Be a Planet. Recorded in improvisational fashion by the guitarist/songwriter Steve Gunn and the pianist David Moore (aka Bing & Ruth), the eight meandering pieces here recreate in sound the fleeting moments and landscapes that feed the American myth: the golden emptiness of the Southwest (“Scattering”), a white New England church at dusk (“Basin”), the rustling nocturne of the backyard (“Rhododendron”). They don’t force you to relax in a new-agey or pseudoscientific way, nor are they vague in their beauty, but instead approach the music with the grounded clarity of folk songs with the song parts scooped out and the spaces left to resonate and glow.