If the outbound light bends sideways, the return light will follow the same path down and arrive at the telescope on-axis. The laser beacon will not appear to wander. Performance Simulations 5.1. First-order Calculations Brent Ellerbroek has calculated the performance of the Gemini baseline AOS under a variety of conditions. The simulations do not take into account uncorrected aberrations from the telescope or focal-plane instrumentation.
Residual jitter can arises from uncorrected atmospheric turbulence as well as telescope wind shake.
For these calculations, the telescope wind shake power spectrum has an assumed form. The baseline assumptions in these simulations are tabulated below. Strehl Ratio as a function of Guide Star Distance A comparison of the Strehl ratio as a function of the distance to the natural guide star. In the case of the NGS AOS, the natural guide star is used for all orders of correction so this plot can also be taken as the variation of the Strehl ratio within the field of view. Note that the difference between the altitude conjugate and pupil conjugate is nearly a factor of two in radius.