http://item.taobao.com/item.htm?spm=a1z10.3.17.52&id=10908423687&Dking Off Axis Guider
离轴导星器
Advantages of Off-Axis Guiding:
-- No mechanical flexure between main and guiding telescope can possibly ruin the tracking accuracy if you use an off axis guider.
-- The load for the mount is much reduced. There is no need for a guide scope and the setup will remain more compact.
-- You work with the main telescope's resolution and focal length, not with the typically lower resolution of a guide scope.
