  Transiting planets around rapidly rotating stars are not amenable to precise
radial velocity observations, such as are used for planet candidate validation,
as they have wide, rotationally broadened stellar lines. Such planets can,
however, be observed using Doppler tomography, wherein the stellar absorption
line profile distortions during transit are spectroscopically resolved. This
allows the validation of transiting planet candidates and the measurement of
the stellar spin-planetary orbit (mis)alignment, an important statistical probe
of planetary migration processes. We present Doppler tomographic observations
which provide a direct confirmation of the hot Jupiter Kepler-13 Ab, and also
show that the planet has a prograde, misaligned orbit, with lambda = 58.6 +/-
2.0 degrees. Our measured value of the spin-orbit misalignment is in
significant disagreement with the value of lambda = 23 +/- 4 degrees previously
measured by Barnes et al. (2011) from the gravity-darkened Kepler lightcurve.
We also place an upper limit of 0.75 solar masses (95% confidence) on the mass
of Kepler-13 C, the spectroscopic companion to Kepler-13 B, the proper motion
companion of the planet host star Kepler-13 A.
