The first tests of the spectrograph have been performed with a neon bulb
as light source with an entrance optics of about f/8 to cover fully the
grating surface. The image spectrum is reproduced below on figure 1 with
the digitized spectrum reported in figure 2. The image shows a regular
spectrum all over the image with no distortion nor vignetting. There is
no distortion on the border of the image. See for instance the 585nm
most intense neon light on the left border of figure 1.
The spectral resolution got with a 25µ inlet slit is about 0.13 - 0.14
nm full with half maximum ( FWHM) that is around 3 cm-1
in the wavenumber units used generally in vibrational spectroscopy.
Figure 1. CCD image of a Neon lamp.
Slit = 25 µ.
Spectrograph placed on bench and illuminated with a
f/8 neon source.