The cosmic conjunction of Alabama Shakes howling to Sunday’s supermoon eclipse to cap the fall edition of Boston Calling not only set up the festival’s highpoint. It forged the kind of moment that’ll live in the memories of those present long after many of the weekend’s bands fade into rock footnotes.

Yet as a last sliver of light rimmed the dark, reddish sphere over City Hall Plaza, the Shakes’ own force-of-nature seemed to be letting the eclipse pass without comment. Singer/guitarist Brittany Howard commanded her own zone, from her raspy, Janis Joplin-esque exortations of “I know, I know!” in “Miss You” to soulful coos about dreaming in “The Feeling,” as she slapped the strings of her Gibson SG.

Finally, Howard stopped. “We got ourselves a blood moon and a lunar eclipse,” the singer told the crowd. “That means it’s time to get weird.”

With that, the Shakes briefly dropped into spacey noodling as the light show on City Hall’s stone ediface rippled into slow oscillation under the eclipse (above, center) and the band slipped into “Gemini,” amid Howard’s ghostly vocal echoes and psych-fuzz guitar beams.

That song lends perhaps the most lunar-esque diversion from classic soul-rock on Alabama Shakes’ eclectic sophomore album Sound & Color. But Howard, who hit Coachella and Bonnaroo in a bleach-tipped coif, returned to earth in fighting trim with short-cropped hair and a print dress, to pump her fist as she took the stage to the PA sounds of Tears for Fears’ “Everybody Wants to Rule the World.” And she still percolated with old-school soul, evoking the Chi-Lites on “Guess Who,” while “The Greatest” lent a Strokes-like punk rush with doo-wop edges (the band skipped its first hit “Hold On,” despite it resurfacing at recent Canadian dates).

God knows the Alabama-bred long shot deserves to rule the music world, and you could say the same for Hozier (below), the nice Irish guy-done-great who impressed in his preceding Boston Calling slot on Sunday. The lanky singer/guitarist with the hair bun stirred up sing-alongs, from the gushing “From Eden” to gospel-ish closer “Take Me to Church.” Like the Shakes, Hozier boosted his sound with backup singers, but his deep tenor stood out the most, making the best of the breezy “Someone New” and giving new import to the Beatles’ “Blackbird.”

Still, Hozier’s palette covered similar soul-blues-rock ground, much like Ben Howard’s set blurred at times as his band built epic, backlit atmosphere around the English singer’s ghostly finger-picking. But especially after just-enjoyable pop from Nate Ruess, who leaned on hits from his band Fun as well as Prince and Elton John, the final night of Boston Calling took a deeper turn towards music with roots and emotion. And in that realm, the Shakes tested the boundaries, found the moon, and held their own. Brittany Howard proved equally unforgettable.