A veritable musical fresco inspired by the cyclical course of the sun, Circa Diem - "almost a day" - invites the listener on a sonic journey following the rhythm of light. From the peaceful darkness of the deep night to the gentle dawn, from the intense brightness of the zenith to the enveloping warmth of the golden hour, to the shifting shadows of dusk, each stage of the day finds it's musical resonance here. The trio Les Heures Bleues weaves it's common thread around Tomaso Albinoni's Opus 1. A first opus for a first project: the idea of a beginning, where all the musical trajectories to come are already hinted at. The cycle of a day thus mirrors the great cycles of life: gestation, birth, maturity, tranquillity, then evanescence. Four sonatas by Albinoni have been chosen and set in dialogue with different moments in the solar cycle, revealing the expressive richness of this Baroque music in the light of passing time. To anchor this one-day journey in our present, contemporary composers were invited to create works based on the light/sonata correspondence that inspired them most: Virginie Tasset, Max Charue, Patrick Leterme, Jimmy Bonesso and Muhiddin Durruoglu. Their contemporary perspectives extend and renew Albinoni's legacy, inscribing this timeless cycle in a resolutely modern sensibility.