  A 10-night asteroseismic observation programme has been conducted in January
2004 with the spectrometer Harps at the ES0 3.6-m telescope. The selected
target, the 6th magnitude F5V star HD 49933, was chosen among the prime
candidates of Corot, the European space mission dedicated to characterize
stellar oscillations mode with high precision photometry measurements. This
star shows important line profiles variations, indicating a surprisingly high
activity with respect to its low rotation rate. However, with the help of tools
developed for disentangling the signatures of activity and oscillations, we are
able to observe its oscillation spectrum in the frequency range [1.2, 2.2 mHz].
We measure the large separation (88.7+-0.4 microHz) and the maximum amplitude
(around 0.4+-0.1 m/s rms), respectively in agreement and marginal agreement
with the predicted values.
