The Spectra-L200 Littrow slit spectroscope has been designed as a robust scientific instrument, and provides the user the ability to collect spectra at low or high resolution, easy to install and use.
The design of the Littrow spectroscope, as applied in the Spectra-L200, uses a fixed, but selectable, entrance slit gap through which the light from the target object is focused (normally from your telescope). The expanding light beam is then reflected from a small precision front surface mirror to a collimating lens. This lens then transmits a parallel light bundle to the reflective diffraction grating. The grating generates a series of spectra. The precision grating used in the Spectra-L200 has a “blazed” profile to maximise the light dispersed into the resulting spectrum. To record different target wavelengths within the spectrum, the grating can be rotated using a precision micrometer. The grating holder is set at a slight angle to the optical axis to reflect the spectrum back to the collimator. The spectrum is then re-focused by the collimating lens to the imaging camera at the focal plane.