Galileo's Eyeglass is a celebratory work for full orchestra with standard instrumentation commemorating Galileo Galilei's discoveries of the four largest moons of Jupiter and the rings of Saturn in 1610. The composition is approximately 14 minutes in duration, and although divided thematically into four parts, the music is continuous. The work exhibits primarily a blend of contemporary styles and compositional elements, yet it is rooted in traditional tonality; furthermore, the piece is interspersed with references to Galileo's life and times, including quotations of a toccata composed by the scientist's brother, Michelangelo Galilei, transcribed from lute tablature. Chapter 1 of Part 1 investigates relevant historical threads extracted from the backdrop of Galileo's life, from reflections on the events that shape the musical program, to the selection and preparation of the period music composed by Galileo's brother. Chapter 2 discusses specific musical components of Galileo's Eyeglass, including form, musical quotations, motivic and thematic material, harmonic language, orchestration, and notation. Chapter 3 examines the principal philosophical themes behind the composition, including expressions of victory of a life well lived in spite of many obstacles. Part 2 contains the orchestral score.