reduce_switch

Reduces the raw beam-switched data by subtracting the off-position from the on-position. The telescope will nod after each nine-point jiggle (or nine-second stare, etc.) which is thus referred to as a switch. At this stage the resulting signal can also be multiplied by the internal calibrator. At present this is not advised since the extent to which microphonically induced noise affects the signal at the chop frequency has not been fully investigated.

The SPIKE_LEVEL option can be used to remove spikes at an early stage. Each position in the map consists of 128 samples which correspond to one second of integration time. If SPIKE_LEVEL is given a value in the range 1-128 the one second of integration will be removed only if this number of spikes is exceeded. The current default SPIKE_LEVEL is 5.