All Tables

Table 1: Computational requirements for various orders of adaptive optics systems. D and d are the telescope diameter and the inter-actuator distance given in meters, $N_{\rm DM}$ and $N_{\rm WFS}$ are the number of DMs and WFSs (>1 implies MCAO), n is the total number of actuators, the column " $\vec{c}=E\vec{ s}$ '' gives the required real-time processing power in Gflops for the matrix-vector multiplication, the column "comp. E'' gives the required number of floating point operations $\times 10^9$ for computing the reconstructor, and the last column gives the required storage space for E in Gb. A Shack-Hartmann type WFS with a Fried geometry of actuators was adopted for the calculations, so that the total number of measurements is $m\approx 2n$ , and the wavefront reconstruction rate was set to 1 kHz. An inter-actuator distance of one meter corresponds roughly to r₀ at 2.2 $\mu$ m, and d=0.25 approximately to r₀ at 0.7 $\mu$ m.
Table 2: Discrete 4-layer model for atmospheric turbulence - h is the layer altitude, $C_n^2/\mu _0=f$ is the fractional turbulence strength per layer, and v is the wind speed.
Table 3: Observational and system simulation parameters.
Table 4: Estimated exponents $\gamma$ in a power-law fit of $\sigma _{\varepsilon }^2\propto D^{\gamma }$ .
Table 5: Strehl ratio simulation results for 2-DM MCAO system with 5 NGSs or 5 LGSs and three different turbulence outer scales L₀. For the case d=0.5 m (left-hand side of table), the square field of view defined by the guide stars measured 40 arcsec in the NGS case and 36 arcsec in the LGS case. For the d=0.8 m case, the field was 67 and 60 arcsec for the NGS and LGS simulations.