RSF motor focuser for RC

Rainbow Astro

RSF motor focuser for RC

Regular price
$ 750.00
Sale price
$ 750.00
Unit price

This item is out of stock but you can place an order now and we’ll ship when it becomes available.

RSF Motor Focuser for RC Telescopes

For use with the RSF-8, RSF-10, RSF-12



This is a secondary mirror moving motor focuser for RC telescopes.

Rainbow Astro's RC line of telescopes are equipped with a crayford focuser, but many users are replacing it with a more accurate focuser. 

It is already in use for large RC telescopes. 

  • All custom-made large RC telescopes use secondary mirror motor focusers.
  • The RSF series is provided as a DIY kit and can be easily installed by anyone.

Perfect compatibility

  • The RSF Series can be easily mounted without damaging your telescope. The location of the secondary mirror will be the same. In addition, the optical axis can be readjusted easily after mounting the motor focuser. 

ASCOM Driver

  • The RSF series focuser supports the ASCOM Driver, convenient and precise control is possible by connecting to PC via USB. You can also create an autofocusing environment through your own independent programming. (this is not supported by Rainbow)


Secondary Mirror Moving

  • It is smaller than the size of the secondary mirror. You can lock the focal plane unit to prevent image shift.
Home & Temperature sensor
  • A home sensor is built in to find the mechanical reference point of the focuser. The hand controller has a built-in sensor to measure the ambient temperature.

Hand controller

  • The hand controller is included as standard, so there is no requirement of use of a PC. The focuser speed can be selected and fine adjustment is possible.

Support various software environment

  • You can use the RSF controller application on your PC via a USB connection (for Windows). It supports ASCOM Platform 6.4.

Easily DIY

  • All components are provided for direct mounting, so anyone can easily install it following the installation manual.


    • Type
      • Secondary mirror moving focuser
    • Motor
      • Stepper motor
    • Focusing stroke
      • +/- 8mm (at focal plane +-/48mm)
    • Minimum step
      • 0.01mm (at focal plane 0.06mm)
    • Operating temp.
      • -20°C ~ 40°C
    • Control
      • Hand controller, Program, ASCOM driver
    • Size
      • Diameter 75mm, Height 82mm(zero position)
    • Weight
      • 560g (Focuser body)

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