Filter installed on the rear tilted substrate of all of the BS systems. It made the filter on the front face of Prism 1 redundant and hence no such filter is reported for BS6. (BS5 and BS6 used prisms from a different batch.). Some of the early systems were brought back into our lab to have this rear filter installed.  

** For BS06 an email from Casey: It is important to note that I made improvements to the spectral FWHM fitting routine as part of another project, which improved the accuracy of the fit compared to a manual fit.  We were under reported the spectral widths before, so while it appears that this instrument preforms worse spectrally than its predecessors, it is actually very similar.  All apologies, please let me know if you want more information.

Stephanie Noted that the shake test showed MUCH less movement than in the previous 4 BS units.

The only difference that I am aware of with this unit is the specification to Leoni regarding the angular tolerance between the line connecting the center of the fibers to the attachment through holes.  This fiber met that specification, which meant that we did not have to over drill or slot the through holes.  I didn't measure the OD of the fiber ferule, but it was very difficult to get it to clear the inside o-ring.  Between the two, I can believe that the fiber alignment was less susceptible to shaking.  It doesn't, however, explain the spectral stability.

casey