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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.
Starlight Instruments 2.0" Adapter RP w/ M109X1 Thread
Starlight Instruments 2.0" Adapter RP w/ M109X1 Thread
Starlight Instruments 2.0" Adapter RP w/ M109X1 Thread

Starlight Instruments 2.0" Adapter RP w/ M109X1 Thread

by Starlight Instruments
SKU SI-A20-3003-10
$130.00 - $130.00
$130.00
$130.00 - $130.00
$130.00
Price Match Policy!
  • Connects 2.0" Feather Touch Rack & Pinion focusers to a telescope
  • Features a female M109x1 thread for secure attachment
  • Designed for heavy imaging payloads requiring a rigid connection
  • Precision machined by Starlight Instruments in the USA
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  • Description
  • FAQ
  • Downloads
  • Warranty

  • Starlight Instruments 2.0" Adapter RP w/ M109X1 Thread

    The Starlight Instruments 2.0" Adapter RP provides the critical, rock-solid connection between a Feather Touch 2.0" rack and pinion focuser and a telescope backplate featuring a male M109x1 thread. This precision component eliminates flexure and ensures perfect alignment for demanding astrophotography applications.

    M109x1 Threaded Connection for 2.0" Rack and Pinion Focusers

    This adapter serves a single, critical purpose: to securely mount a Starlight Instruments 2.0" rack and pinion (RP) focuser onto a telescope. The M109x1 threading creates a rigid, direct-coupled link that is superior to generic adapters, preventing any tilt or shift even with heavy cameras, filter wheels, and off-axis guiders attached. While its specificity is a trade-off—it only fits the M109x1 standard—that specificity is its greatest strength, guaranteeing a perfect fit for compatible instruments.

    Starlight Instruments Build Quality: Precision for Astrophotography

    Machined in-house at Starlight Instruments, this adapter reflects the company's reputation for uncompromising quality. Constructed from high-grade aluminum and finished with a durable anodization, it is built to maintain your imaging train's collimation under load. For astrophotographers, this level of precision means round stars edge-to-edge and the ability to trust your focus, night after night.

  • What is the Starlight Instruments 2.0" RP Adapter with M109x1 thread used for?

    This adapter is designed to connect a Starlight Instruments 2.0" Feather Touch Rack and Pinion (RP) focuser to a telescope that has a specific M109x1 male thread on its rear cell or visual back. It creates a secure, non-flexing mechanical interface.

    Which focusers are compatible with this M109x1 adapter?

    This adapter is specifically made for the 2.0" Rack and Pinion (RP) series of Feather Touch focusers. It is not compatible with Starlight Instruments' 2.0" Crayford focusers, which use a different mounting system.

    How do I confirm if my telescope needs an M109x1 adapter?

    You must check the technical specifications for your telescope, specifically the thread size of the focuser port on the optical tube. If your telescope's manufacturer lists the rear cell thread as M109x1, this adapter is the correct choice for attaching a 2.0" Feather Touch RP focuser.

    Why use a threaded adapter like this M109x1 model for astrophotography?

    For astrophotography, a rigid imaging train is essential to prevent tilt and flexure, which can elongate stars at the edge of the field. A threaded connection like the one this M109x1 adapter provides is significantly more secure than slip-fit or compression-ring adapters, especially when supporting the weight of a heavy camera and accessories.

    Can I use this adapter with a 2.0" Crayford focuser from Starlight Instruments?

    No. The "RP" in the product name signifies it is for Rack and Pinion focusers only. Starlight Instruments' Crayford and Rack and Pinion focusers have different body designs and require their own specific adapters.

    Will this M109x1 adapter fit my Takahashi telescope?

    It depends entirely on the specific model. While some larger Takahashi refractors and astrographs use M109 threads, others use different sizes (like M98 or M110). You must verify the exact thread specification for your particular Takahashi model before purchasing to ensure compatibility.

  • Starlight Instruments 2-Year Warranty