4 Summary

Here we have demonstrated that using integral-field spectroscopic data, it is possible to determine and to correct in the spectra the effects of differential atmospheric refraction, using an a posteriori procedure. This implies an additional advantage with respect to classical sequential 2-D spectroscopic techniques, which are strongly limited by important DAR effects.

In particular, using an observational example, we have indicated how differential atmospheric refraction effects are determined in IFS, and the basic concepts according to which the spectra can be corrected for its effect.

Acknowledgements

We would like to thank Adolfo García his work in the development of the optical bundle. Thanks are also due to the referee, J.R. Walsh, for useful comments. We appreciate the help of Terry Mahoney and Gabriel Perez in the preparation of the manuscript.

The 4.2-m William Herschel Telescope is operated by the Isaac Newton Group of Telescopes at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. We thank all the staff at the Observatory for their kind support.