noun
astronomical spectroscopy; astronomical photometry
Technical term covering both spectroscopy and photometry in astronomy. In practice, 天体分光法 is sometimes used for spectroscopy specifically, but this term encompasses both.
天体分光学は、星の化学組成を調べるのに使われる。
Astronomical spectroscopy is used to investigate the chemical composition of stars.
He earned his doctorate with research in astronomical spectroscopy/photometry.