You want to lift 0.5kg at some undetermined point on a weightless 60cm radial? How rapid acceleration do you need? Once it is moving, speed doesn't matter, but acceleration is all-important.
Let's assume the 0.5kg is at the end of the 60cm wand. It will exert m*A gravitational force on the wand. m=0.5kg, A=about 9.8N/kg (gravity), so you need 4.9N to hold the object stationary. You'll need another 4.9N to accelerate it at the rate of 1g (my assumption.) In this case, the stepper torque will be 0.6m * 9.8N or about 6 Newton-meters. In imperial measure that's about 4.5 foot-pounds; 8638 inch-ounces.
That's a very large stepper motor.