spectrograph

/ˈspɛktrəˌɡræf/
noun
  1. A scientific instrument that separates light or other radiation into its component wavelengths and records the resulting spectrum, used to analyze the chemical composition of substances.
    • A spectrograph attached to the telescope revealed the elements present in the nebula.
    • The astronomer used a spectrograph to study the light from distant stars.
    • The lab's new spectrograph can analyze samples in just a few seconds.