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IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
ZWO Helical Focuser - 1.25"

ZWO Helical Focuser - 1.25"

by ZWO
SKU ZWO-HF1-25
$59.00 - $59.00
$59.00
$59.00 - $59.00
$59.00
Price Match Policy!
  • 1.25" non-rotating helical focuser
  • 6mm of precise focus travel
  • 0.1mm adjustment accuracy
  • M42 female threads for direct OAG attachment
  • Maintains guide camera orientation during focus
4 in stock
Qualifies for FREE Shipping in CONUS on orders over $350.
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • ZWO 1.25" Non-Rotating Helical Focuser

    The ZWO 1.25" Non-Rotating Helical Focuser provides critical focus adjustment for guide cameras, offering 6mm of travel with a repeatable precision of 0.1mm. Its non-rotating design is essential for autoguiding, maintaining perfect guide star orientation while the compact 48.5mm minimum height ensures it fits into tight imaging trains without issue.

    Zero Rotation Guiding with 0.1mm Precision

    Standard helical focusers rotate the attached camera during adjustment, forcing you to re-select your guide star. This ZWO focuser eliminates that problem entirely. The internal 1.25" barrel moves linearly, ensuring your guide camera's sensor remains perfectly stationary so you can dial in focus with 0.1mm accuracy without losing your field of view or calibration.

    6mm of Travel & M42 Threads for ZWO OAGs

    Engineered specifically for ZWO's ecosystem, this focuser features M42 female threads that attach directly to the male threads on a ZWO Off-Axis Guider (OAG). The 6mm of focus travel is ample for achieving a sharp focus with popular mini guide cameras. With a minimum height of just 48.5mm, it adds minimal length to the optical path, helping you meet the back focus requirements of your primary imaging camera and flattener.

    1.25" Single-Speed Reliability

    The ZWO Helical Focuser is a single-speed unit designed for reliability and ease of use. For autoguiding, focus is a set-and-forget adjustment, not a continuous action. This simple, robust mechanical design provides a stable platform for your guide camera, free from the complexity or potential flexure of more intricate focusers, ensuring your guiding remains sharp and consistent throughout the night.

  • What is the main advantage of the ZWO 1.25" Helical Focuser being non-rotating?

    When you focus a guide camera with a standard rotating helical focuser, the camera itself twists. This rotation changes the field of view, forcing you to find and re-select your guide star. The non-rotating design of the ZWO focuser moves the camera straight in and out, so your guide star never leaves its position on the sensor during focusing.

    How do I attach the ZWO Helical Focuser to my ZWO OAG?

    The focuser has M42x0.75 female threads on the telescope side. This allows it to screw directly onto the corresponding male threads of the guide port on a ZWO OAG, creating a secure, threaded connection with no chance of tilt.

    Is the 6mm focus travel on the ZWO Helical Focuser enough for most guide cameras?

    Yes, for its intended purpose with an OAG or a separate guide scope, 6mm of travel is typically sufficient to bring common guide cameras, like the ZWO ASI120MM Mini or ASI290MM Mini, to a sharp focus. It provides enough range to compensate for minor differences in optical setups.

    Can I use the ZWO 1.25" Helical Focuser for a visual eyepiece in my finderscope?

    Absolutely. If your finderscope accepts 1.25" accessories and has an M42-threaded output, this focuser is an excellent upgrade. It allows you to use standard 1.25" eyepieces and achieve a much finer focus than the simple sliding or rotating focusers found on most stock finderscopes, effectively turning it into a small guide scope or rich-field refractor.

    What is the adjustment accuracy of the ZWO 1.25" Helical Focuser?

    The minimum adjustment accuracy is 0.1mm. This level of precision allows you to make very fine corrections to achieve the tightest possible stars from your guide camera, which translates directly to better tracking and sharper final images.

    Is this a dual-speed focuser?

    No, this is a Single Speed Focuser. It is designed for the specific task of precisely setting the focus for a guide camera, which is typically done once at the start of an imaging session. The single-speed mechanism is robust, compact, and perfectly suited for this application.

  • SKU ZWO-HF125
    Focuser Design Non-Rotating Helical
    Speed Single Speed
    Eyepiece Side Size 1.25"
    Telescope Side Thread M42x0.75 Female
    Focus Travel 6mm
    Minimum Height 48.5mm
    Adjustment Accuracy 0.1mm

    • ZWO 1.25” Non-Rotating Helical Focuser

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  • ZWO 2-Year Limited Warranty