Sketch of the complete ARGOS timing sequence from laser pulse launch down to the settling of the adaptive secondary mirror (ASM). The 40 ns laser pulses are generated at a 10 kHz rate. The back and forth propagation in the atmosphere takes 80 μs at which point the Pockels cells are opened for 2 μs (corresponding to a 300 m slab), thus exposing the PnCCD to the laser photons. Ten successive pulses are integrated on the detector, the readout is triggered taking just less than 1ms. The analogue outputs are directly sent to the slope BCU unit, which digitizes the analogue pixel signals and perform all the necessary operation to compute the Shack–Hartmann slopes in a parallel manner, thus minimizing the delay (est. < 100 μs) after the end of the CCD readout. Asynchronous signals (indicated by a ⋆), a particular feature of ARGOS, such as tip-tilt signals from our APD or the FLAO pyramid slopes, can be concatenated to the LGS signals. The final slope vector is transmitted to the real-time computation BCU for reconstruction and control of the ASM. Disregarding the ASM settling time, the total delay is less than 2 ms.