The typical DFM Engineering spectrograph is a Cassegrain instrument incorporating the standard
features of a classical spectrograph used at classification dispersion.
The acquisition and guiding is performed by the Guide Acquire Module™ (GAM™).
The spectrograph optical system consists of the classical configuration and consists of the following
Decker: A decker with different apertures is provided to define the slit length. The Decker
is aluminized to allow acquisition and guiding. The apertures are remotely controlled.
Bilateral Adjustable Slit: The slit width is continuously variable over a wide range. The
slit jaws are polished and set at a 6 degree angle to allow acquisition and guiding from the slit
jaws. The slit width is remotely controlled.
Grating: Gratings are mounted in interchangeable cells. The grating and its cell are attached
to a grating tilt stage allowing the resulting spectra to be positioned in the focal plane of the
camera. A door in the spectrograph housing allows easy access to the grating and its cell so they
may be easily changed. The grating tilt is remotely controlled.