Guider Loop Management

Exposure times

Exposure times should be unsaturated and longer than 5 seconds. If your images are saturated (65k in the raw images) then use the shortest exposure time that allows you to be unsaturated.

Cycle time

Cycle time is the minimum time between the start of two exposures. The time between the start of two exposures should generally be always longer than 5 seconds so set the cycle time to 5 seconds. If the exposure time is longer than 5 seconds then no extra time is needed, nor added between exposures.

PID loops

To stay well centered on a fiducial we may need an integral term in addition to the principle terms for the guide loops. You can set these with:

syscmd -T 'Guider1_tune(kd=0,ki=0.2,kp=0.8)'
syscmd -T 'Guider2_tune(kd=0,ki=0.2,kp=0.8)'
syscmd -T 'ACQ_tune(kd=0,ki=0.2,kp=0.8)'

Where the integral term is the ki and the principle term is the kp.

If you have clouds or some other guiding problems that create intermitant images to be used consider lowering or removing the integral term:

syscmd -T 'Guider1_tune(kd=0,ki=0,kp=1.0)'
syscmd -T 'Guider2_tune(kd=0,ki=0,kp=1.0)'
syscmd -T 'ACQ_tune(kd=0,ki=0,kp=1.0)'

You can clear the guiding terms from memory with the following command:

syscmd -T 'Guider1_clear_fiducial()'
OR
syscmd -T 'Guider1_reset()'

Every time you clear the fiducial or turn the metrology loop on/off it clears the guiding terms.