Astronomy Day is observed in Armenia every September 18 to commemorate the birthday of Victor Ambartsumian, a prominent Armenian scientist and the founder of theoretical astrophysics, born on this date in 1908. The observance was established by the Armenian government to honor Ambartsumian's contributions to science, particularly his research on the evolution of galaxies and his groundbreaking work on atomic nuclei. On this day, various events related to astronomy are organized by both governmental and non-governmental organizations, celebrating the field and its advancements. The celebration serves as a tribute to Ambartsumian's legacy and aims to inspire interest in astronomy among the public.