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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.

Starlight Instruments 2.5" Base Curved w/ Leveling Screws

by Starlight Instruments
SKU SI-BA25CL
$190.00 - $190.00
$190.00
$190.00 - $190.00
$190.00
Price Match Policy!
  • Custom-machined base for curved telescope tubes
  • Designed for Starlight Instruments 2.5" Feather Touch focusers
  • Features integrated leveling screws for precise focuser alignment
  • Provides a rigid, flex-free mounting platform for heavy imaging equipment
  • Requires tube adapter ring A25-2003-1 (sold separately)
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • Starlight Instruments 2.5" Base Curved w/ Leveling Screws

    The Starlight Instruments 2.5" Curved Base provides the critical mechanical link between your telescope tube and a 2.5" Feather Touch focuser, ensuring a rigid, flex-free connection for heavy imaging loads. Designed to mate with the A25-2003-1 tube adapter ring (sold separately), this base uses integrated leveling screws to achieve perfect focuser orthogonality, eliminating the optical tilt that can compromise flat-field imaging.

    A Custom-Machined Foundation for 2.5" Feather Touch Focusers

    A premium focuser is only as good as its mounting. This base is custom-machined to the specific radius of your telescope tube, creating a perfect, flush fit that distributes load evenly and prevents mechanical stress. This solid foundation is essential for supporting heavy imaging trains without introducing flexure or image shift as the telescope tracks across the sky.

    Leveling Screws: Achieving a 0-Tilt Optical Train

    For astrophotography, the focuser's drawtube must be perfectly perpendicular (orthogonal) to the telescope's optical axis. The integrated leveling screws on this base allow you to make fine adjustments to the focuser's orientation, effectively collimating the focuser itself. This capability is crucial for eliminating sensor tilt, ensuring sharp, round stars from corner to corner of your camera's sensor.

    Curved vs. Flat Base: Choosing the Right Mount for Your 2.5" Focuser

    While a flat base is suitable for mounting a focuser to a flat surface, it is the wrong choice for a standard Newtonian or refractor tube. This curved base is specifically engineered to sit perfectly on a rounded surface, eliminating gaps that can lead to instability. The result is a more secure and precisely aligned connection, which is a non-negotiable requirement for serious imaging and visual observation.

  • What information must I provide when ordering the Starlight Instruments 2.5" Curved Base?

    You must specify the outer radius or diameter of your telescope tube in the order notes. Starlight Instruments will custom-machine the base to match this dimension for a perfect fit.

    Does this Starlight Instruments 2.5" base come with the focuser tube adapter ring?

    No. This base is designed to connect to the A25-2003-1 tube adapter ring, which is part of the 2.5" Feather Touch Focuser assembly. The adapter ring must be purchased separately if you do not already have one.

    What is the purpose of the leveling screws on this 2.5" focuser base?

    The leveling screws are for focuser collimation. They allow you to make minute adjustments to the tilt of the entire focuser assembly, ensuring it is perfectly perpendicular to the telescope's light path. This is essential for achieving a flat imaging field without elongated stars in the corners of your photos.

    I'm installing a 2.5" Feather Touch focuser on my 10" f/5 Newtonian. Is this the right base?

    Yes, this is the correct component for your application. When you place your order, you would specify the outer diameter of your 10" Newtonian's tube so the base can be machined for a precise, stable fit.

    How do I adjust the leveling screws on the Starlight Instruments 2.5" base to align my focuser?

    To align the focuser, you typically use a laser collimator or a Cheshire eyepiece placed in the drawtube. By adjusting the leveling screws, you can tilt the focuser until the laser beam is perfectly centered on your primary mirror's center spot and returns back to the collimator's face, indicating the focuser is orthogonal to the optical axis.

    Can I use this curved base on a flat surface, like the rear cell of an SCT?

    No, this base is specifically machined with a curve. Using it on a flat surface would create an unstable, rocking connection. For flat surfaces, you should use the corresponding Starlight Instruments 2.5" Flat Base.

  • Product Type Focuser Base
    Compatibility Starlight Instruments 2.5" Feather Touch Focusers
    Required Adapter A25-2003-1 Tube Adapter Ring (sold separately)
    Tube Profile Curved (Custom Machined to Order)
    Adjustment Leveling Screws for Focuser Collimation

    • Starlight Instruments 2.5" Curved Base w/ Leveling Screws

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    • Mounting Hardware

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  • Starlight Instruments 2-Year Warranty