Mounting CCD filters

ING staff will mount the filters in the wheel(s) for you. The filter cut-out in the wheel is designed to take 2.0inch square filters (in a 51mm square hole); a 47mm clear aperture is provided.

The maximum thickness of filter allowed is 12mm ; filters of thickness less than 3mm will require packing material to stop them moving about within the 3mm deep cut-out hole; filters of thickness 3-12 mm can be held in place with the standard filter masks and adjustable clamps.

It is important that the wheel is in balance, otherwise it might get stuck when observing and moving the filter wheel at large zenith distance. In the standard UBVRIZ or UBVRIH$\alpha$ setups, make sure that the thick filters U, Z, and/or H$\alpha$ are mounted opposite to each other.