Still persisting with the standard candle theme: Omgea cent with a STX16803.
I'm finding the RC field flattner & sensor combination to be quite terse with any focus errors..and the spacing of the sensor to FFC to be very critical. (hence there is a little "rainbowing" around some stars ) anyway...though the world doesn't need it...another Omega Cent here:
http://www.atscope.com.au/BRO/gallery50.html