The Planets dedication notwithstanding, Imogen Holst "would have been both amused and dismayed by the venture." On 24 August 2006, the International Astronomical Union (IAU) defined what it means to be a "planet" within the Solar System. This definition excluded Pluto as a planet and added it as a member of the new category of "dwarf planets", along with Eris and Ceres. Following the IAU decision, Kenyon D. Wilson composed a trombone quintet piece titled "Songs of Distant Earth". The title comes from Arthur C. Clarke's novel of the same name. The composition contains five movements, each named after one of the
Imogen Holst by the cellist Steven Isserlis. In 1976, she took legal action over a recording by Japanese electronic composer Isao Tomita of 'The Planets', calling it 'unworthy of my father's creation'. The record, originally issued on the RCA label, was withdrawn from sale, and vinyl copies have subsequently become very rare. In April 1979 Holst was present when the Queen Mother opened the new Britten–Pears School building in Snape. The building included a new library—the Gustav Holst Library—to which Holst had donated a large amount of material, including books which her father had used in his own teaching career. She had