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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.
SVBONY SV157 1.25-inch Extension Tube (56mm / 70mm)
SVBONY SV157 56mm Extension Tube - 1.25"
SVBONY SV157 56mm Extension Tube - 1.25"
SVBONY SV157 1.25-inch Extension Tube (56mm / 70mm)

SVBONY SV157 56mm Extension Tube - 1.25"

par SVBONY
UGC SV-W9118A
$11.19 - $11.19
$11.19
$11.19 - $11.19
$11.19
Égalisation de prix!
  • Adds a fixed 56mm or 70mm of back focus
  • Standard 1.25-inch barrel diameter
  • CNC-machined aluminum for rigidity
  • Matte black interior prevents internal reflections
  • Solves focusing issues with cameras and certain eyepieces
En rupture temporaire
Alerte de retour en stock
Info disponibilité
Admissible à la livraison GRATUITE aux USA pour les commandes de plus de 350$.
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • SVBONY SV157 1.25-inch Extension Tube (56mm / 70mm)

    The SVBONY SV157 1.25-inch Extension Tube solves common focusing problems by providing a fixed 56mm or 70mm of additional length to your optical path. Constructed from CNC-machined aluminum, it ensures a rigid, non-flexing connection for any standard 1.25-inch focuser, diagonal, or accessory, making it an essential tool for both imaging and visual astronomy.

    Achieve Critical Focus: Adding 56mm or 70mm of Optical Path

    Certain cameras, particularly DSLRs, have sensors that are too recessed to reach focus in telescopes with limited focuser travel. The SV157 extension tube bridges this gap, pushing the focal plane outwards to meet your sensor. It is also essential for using eyepieces that require significant out-travel, especially in reflector telescopes or when using accessories like focal reducers.

    CNC-Machined Construction for a Secure 1.25-inch Fit

    Unlike plastic alternatives, the SV157 is machined from a single piece of aluminum for maximum rigidity and durability. This prevents any sag or tilt, even when supporting a heavy eyepiece or camera, which is critical for maintaining sharp, round stars across the field. The interior is blackened to absorb stray light, protecting your images and views from contrast-robbing reflections.

  • When would I need the SV157 1.25-inch Extension Tube with my Newtonian reflector and a DSLR camera?

    Many Newtonian reflectors do not have enough "out-travel" on their focusers to bring a DSLR camera's sensor to the focal plane for prime-focus astrophotography. The SVBONY SV157 adds the necessary length to the optical path, allowing you to achieve a sharp, infinity focus that would otherwise be impossible.

    I can't get my short-focal-length eyepiece to focus in my Maksutov-Cassegrain. Will the SV157 extension tube help?

    Yes, it's a common issue. Some eyepieces, especially those with Barlows or other optical groups, require more outward focuser travel than a Maksutov's internal focusing mechanism can provide. The SV157 1.25-inch Extension Tube can provide the extra distance needed to bring these specific eyepieces into a sharp focus.

    How do I choose between the 56mm and 70mm SV157 extension tube?

    The choice depends entirely on how much extra focus travel you need. It's best to measure the gap by first trying to focus your equipment and estimating the remaining distance. Since these are fixed-length tubes, choosing the one closest to your required distance is ideal. The 56mm is a good general-purpose starting point, while the 70mm is for systems with a significant focus shortfall.

    Can I stack multiple SV157 extension tubes?

    Yes, you can stack multiple tubes to achieve longer extensions. However, be mindful that creating a very long, unbraced accessory train can introduce flexure or place excessive leverage on your focuser. For very long extensions, a single, longer tube is often a more stable solution.

    Will the SVBONY SV157 add any optical distortion to my view?

    No. Because the SV157 is a hollow tube with no lenses or glass elements, it does not alter the optical properties of your telescope. It purely serves as a mechanical spacer to extend the focal plane, so it will not introduce chromatic aberration, astigmatism, or other distortions.

    Is the inside of the SV157 tube blackened to prevent reflections?

    Yes, the interior of the SVBONY SV157 extension tube is painted matte black and machined with light-baffling ridges. This is a critical feature that prevents stray light from reflecting off the inner walls and reducing the contrast of your images or visual field.

  • Barrel Size 1.25 inch
    Available Lengths 56mm / 70mm
    Material CNC-machined aluminum

    • SV157 1.25-inch Extension Tube

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  • SVBONY Warranty Policy