At present, SHOC has one 8-position filter wheel, containing UBVRI, a clear filter to match the focus of the Bessell filters, and two empty slots. The SHOC software identifies the filter in each position. There is also a 6-position neutral density wheel that can be used with or without the Bessell filters in the beam. '''Filters must not be removed from the filter wheels.'''
== Observing limits ==
=== Meteorological constraints ===
The dome must be closed when any of the following weather limits is reached:
* '''Humidity''': T<sub>external</sub> - T<sub>dew</sub> ≤ 1.5
* '''Wind speed''': 60 km/h
* '''Heavy cloud'''
=== Meteorological information ===
The following should be used for regular monitoring of external conditions while observing:
* DIMM seeing data and all the weather stations on the plateau are summarised on [http://suthweather.saao.ac.za this page]
* For assessing sky conditions, SALT and LCO operate '''all sky cameras''', also available on the website above.
== Commissioning Aids ==