Chile’s self-appointed, one-man Truth and Reconciliation Commission, Patricio Guzmán has devoted the past four decades to chronicling the short-lived Allende administration and the Pinochet dark ages that followed, long after his countrymen wanted him to stop. At first blush, though, his new documentary detours toward astronomy, landing rather Herzog-ishly in the Atacama Desert, the elevation and absolute dryness of which make it one of the globe’s optimal observatory locations. Guzmán uses the stars’ distance to ruminate on the nature of time—as in, everything, even light, even this, is in the past. He eventually winds his way around to how time has treated the ghost-town-turned-concentration-camp of Chacabuco, its ex-prisoners, the dumped bones of disappeared Pinochet victims, and the tough, striking old women who still scour the desert plateau on foot hunting for remains. Guzmán fugue-weaves all over the place, montage-cutting from the lunar surface to giant close-ups of calcified bone, and the film’s philosophical musings slowly funnel down into a silent yowl of rage and a desperate plea for remembrance. (If Guzmán is to be believed, Chileans have an even stronger urge to forget than Americans do.) Often stark and ravishing, Nostalgia for the Light is most moving as a manifestation of the filmmaker’s stubborn righteousness. (Also screening Sat.–Sun. at 3 p.m. is Guzmán’s five-and-a-half hour The Battle of Chile, Parts 1–3.)