3D Spectroscopy of Wind Driven Nebulae: The Large Western Knot in the Halo of NGC 6543 David Mart´ ın-Gord´ on 1 , Jos´ e M. V´ ılchez 1 , Angels Riera 2,3 , and Sebasti´an S´ anchez 4 1 Instituto de Astrof´ ısica de Andaluc´ ıa, CSIC. Apdo. 3004, 18080 Granada - Spain. dmg@iaa.es, jvm@iaa.es 2 Departament de F´ ısica i Enginyeria Nuclear, Universitat Polit` ecnica de Catalunya, Vilanova i la Geltr´ u - Spain. angels.riera@upc.es 3 Department d´ Astronomia i Meteorologia, Universitat de Barcelona, Barcelona - Spain. 4 Calar Alto Observatory Centro Astron´omico Hispano Alem´an, 04004 Almeria - Spain. sanchez@caha.es Summary. The history of stellar mass loss of massive and intermediate mass stars is written in their wind driven-nebulae. Fast winds can provide an extra source of heating for the thermal balance of the haloes of PNe and WR nebulae. The comparison of the emission of different states of ionization or different emission conditions provides a direct evidence for finescale structure within the halo of the nebula. In this work we present new results of 3D spectroscopy taken with the PMAS/PPAK Instrument for the halo of the nebula NGC 6543. The large Western Knot in the halo of this young planetary nebula is an excellent place to derive new spectroscopic constraint in order to evaluate the role of photo-ionization as the main excitation mechanism. Key words: Nebulae: planetary nebulae – Nebulae: photoionization – Nebulae: shock excitation – Nebulae: 3D spectroscopy 1 Introduction The history of stellar mass loss is written in the extended wind-driven nebulae around massive (WRN) and intermediate mass stars (PNe). Fast winds can produce shock excitation of the interstellar medium in the haloes of PNe and WR nebulae providing an extra source of heating for their thermal balance. We are performing an observational program aimed to evaluate the realis- tic impact on the interstellar medium of these effects. A search for possible footprints of shock-heated gas in the extended haloes of wind-driven nebulae has been carried out using deep multi-filter imaging of a sample of WR and PNe nebulae. The comparison of the emission of different states of ioniza-