Filters for the 4m R-C Spectrograph
Two filter bolts that each can hold four filters and a clear position are available. The lower filter bolt contains neutral density filters; the upper filter bolt contains either order-sorting filters or additional neutral density filters. An additional filter holder for a single order-sorting filter can be manually inserted into the beam if required.
Note that any filters used are all located behind the slit, and so will alter the collimator focus. The final collimator focus value should be determined with the desired filters in place.