For a detailed Finder Chart and rotation setting see Kyle Kaplan's software. For rough rotations use the lookup table below.

393 = Default Encoder Setting at 90 deg. PA (slit east to west)

Position Angle (Start north and go east, N=0, E=90, S=180, W=270 degrees, Default = 90 deg slit oriented east-west)

(Encoder Setting) = 393 - 90 + (Position Angle) = 303 + (Position Angle)

Encoder should not go further than +/- 180 degrees from the nominal 90 degree position to avoid entangling wires and hoses.  The encoder setting limits are: