  We report the detection of a Jupiter-mass planet discovered with the SOPHIE
spectrograph mounted on the 1.93-m telescope at the Haute-Provence Observatory.
The new planet orbits HD109246, a G0V star slightly more metallic than the Sun.
HD109246b has a minimum mass of 0.77 MJup, an orbital period of 68 days, and an
eccentricity of 0.12. It is placed in a sparsely populated region of the period
distribution of extrasolar planets. We also present a correction method for the
so-called seeing effect that affects the SOPHIE radial velocities. We
complement this discovery announcement with a description of some calibrations
that are implemented in the SOPHIE automatic reduction pipeline. These
calibrations allow the derivation of the photon-noise radial velocity
uncertainty and some useful stellar properties (vsini, [Fe/H], logR'HK)
directly from the SOPHIE data.
