This 3" Rack and Pinion from Astrograph is a quality made focuser with excellent smoothness and load capability of up to 6kg.
This focuser has been designed to offer connection to telescopes with common threads. At the end of the focuser, the common thread of M68 is used, allowing easy fitting of many common accessories including a 2.5" field flattener. Input from imagers resulted in the focuser having a high load capacity with zero tilt. Our focusers does not use ballbearing supports which tend to tilt, our focusers use a teflon support which guarantee a complete lack of play due to heavy loads.
The focuser attaches to the tube using a 117x1 ID thread. This is the same size as the thread used on GSO telescopes such as the Ritchey Chretien and Cassegrain models. The standard focuser on those telescopes is particularly poor and not in keeping with the quality of the rest of the telescope. As such this focuser provides a significant upgrade at a relatively modest price. In addition this focuser can be motorised using the Optec SVX30 Thirdlynx or Directsync SV motor kits providing a premium motor focus option.
As this focuser is intended for use as a replacement for the GSO RC and Cassegrain Telescope focusers, it is specified with a short focus travel of 45mm. It is 110mm long from the M117 thread to the 2" clamp.
The focuser is supplied with
Adapter M78x1 OD to M82x1 ID (This allows direct connection with the APM Large Reducer or Flattener which use M82). This adapter is separate.
Adapter M78x1 OD to M74x1 OD / M68x1 ID (M68 is a common adapter and allows direct connection to the 2.5" Flattener and also the Tecnosky RC Corrector)
Adapter M74x1 ID to 2" with brass clamp and 3 set screws
Adapter 2" to 1 1/4"