How Does a Spectrograph Work? A spectrograph passes light coming into the telescope through a tiny hole or slit in a metal plate to isolate light from a single area or object. This light is bounced off a special grating, which splits the light into its different wavelengths (just like a prism makes rainbows).

What does a spectrograph do?

A spectrograph is an instrument that separates incoming light by its wavelength or frequency and records the resulting spectrum in some kind of multichannel detector, like a photographic plate.

How does a spectrograph CCD work?

The slit on the spectrograph limits the light entering the spectrograph so that it acts as a point source of light from a larger image. ... This disperses the light into component wavelengths which can then by focused by a camera mirror into a detector such as a charged-couple device (CCD).