Guider
An SBIG SG-4 autoguider was added to the Moore Observatory CDK20 in October 2009. It is mounted on the bracket originally designed to hold a Nikon DSLR and wide-field lens under the telescope. However, in that position, the guider will not clear the mount as the telescope rotates in declination. The bracket was moved to the "top" of the telescope and secured to the central truss ring by two 1/4-20 stainless steel allen-head cap screws. The Nikon attachment plate has a rib on the underside that reduces flexure.
The guider is presently used with a Takahashi 60 mm diameter apochromatic refractor with a focal length of 355 mm. The assembly is held by a Takahashi tube mount, and bolted to the Nikon plate with a single 1/4-20 screw. The strength of this attachment derives from the large contact area.