Radial velocity (cz) with respect to the CMB: v3k
Finally, the radial velocity is also expressed in the reference frame of
the Cosmic Background Radiation. This velocity is noted v3k.
It is calculated from the heliocentric velocity v using the total
solar motion of 360 km/s towards the direction defined by the
B1950 equatorial coordinates B 11.25 H - 5.6 deg (Lubin & Villela 1986).
Where theta is:
cost(theta) = sin(de3k) sin (de1950) + cos (de3k) cos(de1950) cos(al3k - al1950)
Other velocities in the database are:
vrad,
vopt,
v,
vgsr,
vlg,
vvir.