How do the guiding rates, 1.0x, 0.5x, 0.25x etc translate to motion of the mount? What are the units? If I am using PHD guiding and it gives a 50ms pulse and the keypad guide rate is set at 1.0x does the motor or mount move a specific amount? Is this translated to a certain number of steps of the servo motor? In the AP 900 is there a specific number of "steps" per arc minute of RA movement?