Heliossea is an intermedia work for flutes and live electronics composed by Alessandro Grego in 2003 and premiered in Trieste on 21 June – the summer solstice – of the same year. It is a meditation on the rising of the sun, starting from the first ray of light at dawn breaking over the horizon. Astronomical data about the phenomenon, translated into sound using Grego’s custom-designed software, plays a crucial role in shaping the music. In 2023, to mark the 20th anniversary of Heliossea’s premiere, Alessandro Grego created a new version titled Heliossea XX. This updated rendition was performed for the first time on 3 September 2023, at the Miramare Castle Park in Trieste. The work is conceived as a tribute to Margherita Hack and her contributions to science and Italian culture. The new version of Heliossea, produced by the Prodigys Group, was realised in collaboration with INAF-OATS, which oversaw the scientific aspects of the project, and the “Studio di Sonologia Computazionale” in Padua, under the direction of Alvise Vidolin, which managed the surround sound diffusion. Astronomical data provided by the National Institute for Astrophysics (thanks to its director Fabrizio Fiore and Massimo Ramella) enhanced the work’s precision and immersive quality.