New live discs emerge from the otherworldly Sun Ra

"Sun Ra: Disco 3000: Complete Milan Concert 1978," a hard-to-find, but sensational set by the pianist (above, in 1984), is among a bunch of old material that has been unearthed recently. (DARRYL PITT/RETNA/file 1984)

A synth bass line that repeats and repeats. The rudimentary pattern of a rhythm machine. Exploratory noodling on a Moog synthesizer. The drum machine, gone. Splashes of cymbals. A probing trumpet. Space-age synth chords. Another pattern from the machine. The trumpet, still blowing. Drums, saxophone. Everyone soloing at the same time. Chaos, organized. Suddenly, a groove and a chant: "Space is the place. Space is the place. Space is the place. Yeah, space is the place." The groove disappears as quickly as it emerged, and the music erupts into fury - organ swirling, drums crashing - and swerves back and forth between electronic dance parody and free jazz. It goes on for 26 minutes. This beautiful mess is "Disco 3000," the opening track of a Sun Ra album of the same name that was recorded 30 years ago today.

You're forgiven if you missed it the first time around. Only now is the concert getting its proper release, on a perfectly mastered two-disc set from a British label called Art Yard. The set, "Sun Ra: Disco 3000: Complete Milan Concert 1978," is difficult but not impossible to find. It's not available on Amazon or in most record stores, but it can be ordered - at a reasonable price - from several reputable websites, including that of New York's Downtown Music Gallery (downtownmusicgallery.com).

It is worth seeking out; "Disco 3000" constitutes a Holy Grail of Sun Ra's small-ensemble recordings.

Sun Ra - nee Herman "Sonny" Blount (1914-1993) - recorded prolifically for his own Saturn label, but the LPs were notorious for their poor audio quality. Sun Ra wasn't the most agile pianist (many people considered him a fraud), and his groups never seemed well rehearsed, but his concepts, his aesthetic - his sound - conferred upon him and his "arkestra" a cult status that remains as strong today as it was when he was alive.

If there's any doubt about his perseverance, look no further than the most recent edition of the Penguin Guide to Jazz, which devotes eight pages to Sun Ra, the same number it gives to Oscar Peterson and more than it sets aside for Dave Brubeck, Bill Evans, or Herbie Hancock.

In the 21st century, Sun Ra's music is experiencing a renaissance, with several new recordings appearing each year, some of which now rank among his best efforts. Three years ago, ESP-Disk discovered and issued "Heliocentric Worlds Vol. 3," a follow-up to the famous sessions from 1965. In 2006, the label Golden Years of New Jazz pressed "Springtime in Chicago," a sprawling concert recording from 1978 that featured a lively mix of big-band-era standards (Fletcher Henderson's "Big John's Special," Coleman Hawkins's "Queer Notions"), and the Sun Ra Arkestra's own oddities ("Calling Planet Earth," "Lights on a Satellite").

Momentum has been building in the past year. A new California-based label called Transparency has apparently discovered a trove of recordings that Sun Ra and his bands made during rehearsals, concerts given in warehouses, and shows performed in small clubs. Four sets in the so-called "Lost Reel" series came out last year, and four more are supposedly on the way soon. (Attempts to reach anyone connected with Transparency failed.)

The Atavistic label, well regarded for its Unheard Music series of archival material, remastered a pair of bizarrely enjoyable recordings last year: "The Night of the Purple Moon," a small group outing that has Sun Ra poking around on a new synthesizer, and "Strange Strings," a difficult listen that has several musicians going wild on a stringed instruments. Next week the label will release an unearthed record called "Some Blues But Not the Kind That's Blue."

The 1978 concert from Milan, however, merits particular attention. Rarely has Sun Ra been recorded and preserved this crisply, and rarely has he produced such accomplished music or performed such diverse material in one concert. In fact, this just might be the finest small-group session he ever led.

Sun Ra (playing piano, organ, synthesizer, and rhythm machine), tenor saxophonist John Gilmore, trumpeter Michael Ray, drummer Luqman Ali, and vocalist June Tyson (featured on a few songs) interact with both sympathy and discourse. Gilmore was, of course, a gifted saxophonist, but the other sidemen seem more technically proficient than one is accustomed to hearing from Sun Ra's bands.

In new liner notes, Ray explains that Sun Ra invited him to Rome to make an album and that they ended up rehearsing all day for several days before the Jan. 23, 1978, show in Milan. The pianist - who was obsessed with both ancient Egypt and outer space - gave the trumpeter an endless stream of advice during their practices. "It was like having someone erase your main frame and reboot your hard drive!" Ray writes. "Sunny always said expect the unexpected. 'We might have a gig on Mars one day, so you got to be swinging on your horn, because they don't party like earthlings."'

If Sun Ra's goal was to make music that sounded not of this earth, then he succeeds superbly as the opening track segues into "Sun of the Cosmos." He rumbles along on the high and low ends of his synthesizer as Ali thrashes on the drum kit, conjuring images of an intergalactic battle, Atari-style. How Sun Ra reconciles such weirdness with the gorgeous piano solo that introduces the next piece, "Echoes of the World," or his tender reading of "Over the Rainbow" later in the concert, is anyone's guess. But this is his world, not ours.

Steve Greenlee can be reached at greenlee@globe.com.