Angular velocity is the speed at which an object travels in terms of radians or degrees, not any unit of length.
One full revolution around the sun: 2*pi radians, 365 days
2*pi/365 = 0.0172 rad/day
1 day = 86400 seconds, so to convert from rad/day to rad/s, simply divide by 86400.
0.0172 rad/day = 1.99238 * 10^-7 rad/s
