Vixen Telescope SX2 Mount Description Declination body acting as part of counterweight. The massive motor units are placed in the lower part of the declination body so that the center of balance of the SX2 shifts below the intersection of the RA and Dec axes. This makes the lower portion of the declination body perform as a counterweight and allow the mount to work with less counterweight. Retractable counterweight bar. Durable stainless steel is used for the counterweight bar. It is moved back into the mount body for storage by loosing the bar lock lever. It is convenient for transporting the mount and for easy set up. STAR BOOK ONE dual-axis controller. The SX2 mount comes with the STAR BOOK ONE controller featuring a variety of functions in a simple design. Designed for ease of use, the lightweight STAR BOOK ONE moves the SX2 mount on the X and Y dual axis (RA and Dec directions). Versatile tracking options are available in addition to sidereal and solar tracking rates. Backlash compensation, autoguider port and built-in red LED light are some of the useful functions of the STAR BOOK ONE. STAR BOOK TEN star chart go-to navigation controller is available as optional. The SX2 mount works with the STAR BOOK TEN controller, featuring an intuitive star chart Go-to system with high definition color LCD display. Incorporating over 270,000 objects, the STAR BOOK TEN identifies and tracks your trarget easily. This controller is not included with the SX2 mount.