  We present rotation curves of the Galaxy based on the space-velocities of 197
OB stars and 144 classical cepheids, respectively, which range over a
galactocentric distance interval of about 6 to 12 kpc. No significant
differences between these rotation curves and rotation curves based solely on
radial velocities assuming circular rotation are found. We derive an angular
velocity of the LSR of Omega_0 = 5.5 +/- 0.4 mas/a (OB stars) and Omega_0 = 5.4
+/- 0.5 mas/a (cepheids), which is in agreement with the IAU 1985 value of
Omega_0 = 5.5 mas/a. If we correct for probable rotations of the FK5 system,
the corresponding angular velocities are Omega_0 = 6.0 mas/a (OB stars) and
Omega_0 = 6.2 mas/a (cepheids). These values agree better with the value of
Omega_0 = 6.4 mas/a derived from the VLA measurement of the proper motion of
SgrA*.
