Filters for the Echelle Spectrograph

A pre-slit wheel for 2 x 2-inch filters, and a post-slit wheel for 1 x 1-inch plus one larger filter are available. However, the pre-slit wheel is normally not installed since it partially obstruct the slit- viewing TV; in principle it can be installed through a special hatch when the spectrograph is on the telescope. The following filters are mounted in the post-slit wheel: 

      Indicator Position        Filter               Thickness

           1               1.0 mag neutral density       3mm
           2               2.5 mag neutral density       3
           3                    GG 385                   3
           4                    GG 495                   3
           5                    RG 610                   3
           6                    KG 1                     3
          Special               CuSO4                    5
          Open                   --                      -

Any other appropriately-sized filter from the CTIO Filter List can be used. Note that the post-slit filters affect the spectrograph focus and they must be in place when the final focus value is determined.