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.
Guide Acquire Module
Smart Auto Guider
Articulated Relay Eyepiece
Collimator: An off axis parabolic collimator is provided. The collimator
is mounted on a stage allowing remote control of the focus.
Filter Wheel: A remotely controlled filter wheel is provided to allow the use of order separation
Camera Lens: The typical camera consists of a commercial lens assembly mounted to a manually
removable stage. Additional stages may be provided with different focal length lens assemblies.
Detector: A commercially available cooled and integrating CCD camera is provided.
Housing: The spectrograph is contained within an aluminum dust tight housing. A front flange
allows attaching the spectrograph to the bolt pattern on the Guide-Acquire-Module.