spectrograph
Concise Oxford English Dictionary © 2008 Oxford University Press:
spectrograph/ˈspɛktrə(ʊ)ɡrɑːf/
▶noun an apparatus for photographing or otherwise recording spectra.
– derivatives
spectrographic adjective,
spectrographically adverb,
spectrography noun.
spectrographic adjective,
spectrographically adverb,
spectrography noun.
'spectrograph' also found in these Oxford entries:

