The Astro-Physics mounts use servo motors which have 0.05 arc second steps,
the G11 and G8 use stepper motors which have 0.5 arc second steps. The new
Losmandy goto system replaces the stepper motors with servo motors that have
0.1 arc second steps. I assume that the chain of gears reduces the effect
of such a large step size, but I have heard that for visual planetary
observing it's better to turn off the motor (slew west at 2X).
Sean Houghton
shought1@...
San Diego, Ca
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I'm not sure what "torque and swing" means. The stepper motor rotates a
worm, which in turn rotates a worm gear, which in turn rotates the polar
shaft. I believe this is how all quality mounts drive their polar axis,
including Astro-Physics, Takahashi, Mountain Instruments, Parallax, etc.
The size of each step is important, and so is the amount of vibration
introduced. If the steps are too large, then they are visible (either to
the naked eye or to the camera). The size of the steps on the GM8 and G11
is small enough so that this isn't a problem, either visually or when
imaging.
