[ATM] Determining Stepper Motor Size

[stan_gorodenski at asualumni.org (Stanley A. Gorodenski)]

I am attempting to determine if a particular stepper motor, 75 oz-in 
torque, will be sufficient to be able to slew in declination, given a 
particular reduction ratio. Because a telescope tube assembly is, 
ideally, perfectly balanced, aside from friction it seems to me the 
major determining factor in sizing a stepper motor should be the 
tangential acceleration (in beginning physics text books this is 
considered to be a constant velocity vector rather than an acceleration) 
to get to a particular slew rate (the rate may be 4 degrees per second). 
Once the tangential acceleration is determined, then one can compute the 
force this represents which then would directly be used to compute 
torque. This value would then be compared to the torque rating of the 
stepper motor. Is this the correct procedure to determine the stepper 
motor torque needed? If so, what is the generally accepted acceleration 
value used?

Stan