5 Conclusions

Knowing the size of the isokinetic patch can become important for some of the new techniques proposed to solve the tilt problem. Furthermore, the same perturbations observed in an elongated LGS can be easily seen observing the edge of the Moon. In this experiment several images of the edge of the Moon have been obtained with an optical system able to evaluate both the size of the isokinetic patch and r₀. A further run of the described instrument at the Telescopio Nazionale Galileo's (TNG) site in Canary islands (Barbieri 1997) could be very interesting to tune one's expectations about the effective performances of the Adaptive Optics module (Ragazzoni & Bonaccini 1995; Ragazzoni et al. 1997) which is actually under construction and will be permanently mounted at the Nasmith focus of the TNG.

Acknowledgements

Special thanks are due to Enzo Bellettato, Jacopo Farinato and to Marina Rejkuba for their helpful contribute during the observations and for the realization of the instrumentation described in the paper.