  We designed and constructed a special instrument to enable the determination
of the stellar's spin orientation. The Differential image rotator for Stellar
Spin Orientation, DeSSpOt, allows the simultaneous observations of two
anti-parallel orientations of the star on the spectrum. On a high resolution
\'echelle spectrum, the stellar rotation causes a slight line tilt visible in
the spatial direction which is comparable to a rotation curve. We developed a
new method, which exploits the variations in these tilts, to estimate the
absolute position angle of the rotation axis. The line tilt is retrieved by a
spectro-astrometric extraction of the spectrum. In order to validate the
method, we observed spectroscopic binaries with known orbital parameters. The
determination of the orbital position angle is equivalent to the determination
of the stellar position angle, but is easier to to detect. DeSSpOt was
successfully implemented on the high resolution Coud\'e spectrograph of the
Th\"uringer Landessternwarte Tautenburg. The observations of Capella led to the
determination of the orbital position angle.
