Solar research and instruments
Hale graduated from MIT in 1890 and established his reputation through solar spectroscopy and instrumentation. His spectroheliograph and related tools enabled images in selected solar spectral lines to be recorded and compared.
References: [1]
Building major observatories
He organised funding, instruments and sites for large observatories. Yerkes opened in 1897, and Hale became Mount Wilson’s director in 1904. He subsequently promoted larger telescopes; Palomar’s 200-inch telescope was dedicated in 1948, ten years after his death.
Institutions and international cooperation
Hale helped transform local education in Pasadena into Caltech and promoted the Astrophysical Journal, the National Research Council and international scientific cooperation. His work connected instrumentation and finance with research and scientific training.
References: [1]