Re: Does this mount use Sitech controller software?

Don W

Hi Dan A
Absolute encoders do a remarkable job virtually eliminating periodic error.  That is with direct drive mounts and with servo worm/gear mounts.  The key is that the absolute encoders are on the mount axis for RA and Dec or Alt/Az or Alt/Alt mounts.  A recent example of this is the AstroPhysics Mach2 mount.  All these mounts require alignment to Earth - Polar Alignment or perfect Latitude/Longitude.  Non-equatorial mounts also require very accurate encoders on the rotators used to compensate for rotating sky.  Dan uses an Alt-Alt mount able to track satellites from horizon to horizon - something a GEM can't do easily.

The only thing direct drives do that worm drives can't is high speed slewing.  They both can rely on axis absolute encoders - no PE, but require alignment to operate properly.

One note is that direct drive require excellent (perfect) balance.  When power is off, direct drive doesn't hold the axis, unless there is a powered brake - the mount will fall to the balance point.

Don W

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