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Starlight Instruments 2.0" Adapter RP w/ M109X1 Thread

SKU SI-A20-3003-10
Original price $130.00 USD - Original price $130.00 USD
Original price
$130.00 USD
$130.00 USD - $130.00 USD
Current price $130.00 USD
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  • Connects 2.0" Feather Touch Rack & Pinion focusers to a telescope
  • Features a male 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
  • Specifications
  • In the Box
  • 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 or Starlight base featuring a female 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. It uses the same M109x1 thread as Starlight's standard 3" focusers and also fits Starlight's BA30FL and BA30CL bases. 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 female M109x1 thread on its rear cell, or a Starlight BA30FL or BA30CL base. It creates a secure, non-flexing mechanical interface.

    Which focusers are compatible with this M109x1 adapter?

    This adapter is for the FTF2015BCR-RP 2.0" Rack and Pinion Feather Touch focuser. 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.

  • Kind other (state): tube adapter with M109x1 thread for the 2.0in Feather Touch rack and pinion focuser
    Telescope-side connection thread: other (state): M109x1; gender: male
    Camera-side connection thread: other (state): 2.0in Feather Touch rack and pinion focuser (FTF2015BCR-RP); gender: None
    Warranty 2 years
    • Starlight Instruments 2.0" Adapter RP w/ M109X1 Thread

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  • Starlight Instruments 2-Year Warranty