This instrument may be used to photograph spectra, and is particularly well adapted for use with SCTs. Here are some of the stars I've observed and a description of their spectra. This is a fascinating observational project, and a nice change of pace. Spectral lines are formed by electrons jumping between different energy levels in the atoms in the star's outer layers. Enough electrons jumping between any two energy levels of a given element will result in a spectral emission or absorption line at a characteristic wavelength.
Cool stars have fewer atomic collisions and have weaker absorption lines.
Hot stars are hopping with frequent atomic collisions which prevent stable molecules, and thus prevent the dark molecular bands. O stars - sorry, no hot hot blue stars of significant magnitude were visible or of a high enough magnitude for spectral detection these nights. The three Orion belt stars are O class, so we'll observe them later in the year. What we would see if we could is ionized helium and the hydrogen lines weak but still prominent. Neutral helium, with stronger hydrogen lines are present.