Captain Beyond were an odd duck even for a supergroup — a singer from Deep Purple (but neither of the ones you’re thinking of), guitarist and bassist from Iron Butterfly, drummer from Johnny Winters, signed to a label better known for Southern rockers like the Allman Brothers despite their progressive leanings. And that Southern twang does show through on bluesier space excursions like “Myopic Void,” part of the opening “Dancing Madly Backwards on a Sea of Air” suite. It’s about as seventies as leisure suits and shag carpets but it’s aged significantly better — their hard rockin’ pedigrees bring unexpected swing to their journeys into the beyond.