Skip to content
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"
SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"

SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25"

by SVBONY
SKU SV-W9105D
CA$77.00 - CA$77.00
CA$77.00
CA$77.00 - CA$77.00
CA$77.00
Price Match Policy!
  • 7mm to 21mm continuous zoom focal length
  • 57° to 40° variable apparent field of view
  • 18mm to 16.3mm of consistent eye relief
  • Fully multi-coated (FMC) 6-element optics
  • Standard 1.25" barrel with M28.5*0.6 filter threads
Backordered
Request Stock Alert
Availability Info
Qualifies for FREE Shipping in Canada on orders over $500.
Visual Simulator Preview
Visual Simulator Instant FOV Preview

Preview your eyepiece's FOV

Simulate the exact field of view of the SVBONY SV135 7-21mm 60-40° Zoom Eyepiece - 1.25" with your specific telescope.

Launch Visual Assistant
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • SVBONY SV135 1.25" 7-21mm Zoom Eyepiece

    The SVBONY SV135 1.25" Zoom Eyepiece replaces a case full of eyepieces with a single, versatile unit, offering a continuous focal length from 7mm to 21mm. Its 6-element, 4-group optical design delivers a variable apparent field of view from 57° down to 40°, while maintaining a generous eye relief of 18mm to 16.3mm for comfortable viewing. Weighing just 133g and threaded for standard M28.5*0.6 filters, this eyepiece provides seamless magnification changes for any telescope with a 1.25" focuser.

    7-21mm Linear Zoom: Find, Center, and Magnify in One Motion

    The core of the SV135 is its linear zoom mechanism, which allows you to change magnification smoothly without swapping eyepieces. You can start at the 21mm setting for a wide, low-power view to easily locate and center a target like the Orion Nebula (M42). As you twist the barrel, you can seamlessly increase power up to the 7mm setting to resolve fine details, such as the individual stars of the Trapezium, all without ever taking your eye from the focuser.

    Fully Multi-Coated Optics: A 57° to 40° Variable Field

    The SV135's 6-element optical system features fully multi-coated (FMC) surfaces to maximize light transmission and contrast. At its widest 21mm setting, the eyepiece presents a 57° apparent field of view, ideal for framing large star clusters. As you zoom to the 7mm setting for higher power, the field of view narrows to 40°—a necessary trade-off in zoom eyepiece design that provides the power needed for resolving planetary details or splitting tight double stars.

    Comfortable Viewing: 18mm Eye Relief and a 1.25" Barrel

    Designed for accessibility, the SV135 maintains a long eye relief ranging from 18mm at 21mm to 16.3mm at 7mm. This consistency makes it an excellent choice for observers who wear glasses, eliminating the need to remove them to see the full field. The standard 1.25" barrel ensures compatibility with virtually any telescope, and its lightweight 133g metal body won't create significant balance issues on smaller mounts.

    SV135 Zoom vs. Fixed Plössls: Convenience vs. Field of View

    While a set of fixed focal length Plössl eyepieces will offer a consistently wider field of view (typically 50-52°), they cannot match the operational simplicity of the SV135 zoom. The ability to fine-tune magnification to perfectly frame an object or adapt to changing atmospheric seeing conditions is a significant advantage.

    • Fixed Eyepiece Advantage: Generally provides a wider, flatter field and potentially higher light transmission due to a simpler optical design.
    • SV135 Zoom Advantage: Unmatched convenience by eliminating eyepiece changes, making it ideal for outreach, travel scopes, or observers who prioritize a fluid viewing experience over a maximized field at high power.

  • How does the SVBONY SV135's field of view change as I zoom?

    The apparent field of view on the SV135 is variable. It is at its widest, 57 degrees, at the 21mm focal length setting. As you increase magnification by zooming towards the 7mm setting, the field of view narrows to 40 degrees. This is a normal characteristic of zoom eyepiece designs.

    Is the 18mm eye relief on the SV135 suitable for eyeglass wearers?

    Yes, absolutely. The eye relief ranges from 18mm to 16.3mm, which is considered long and provides ample distance for most eyeglass wearers to see the entire field of view comfortably without having to press their glasses against the lens.

    Can I use standard 1.25" filters with the SVBONY SV135 zoom eyepiece?

    Yes. The barrel of the SV135 eyepiece is threaded with the standard M28.5*0.6 thread pitch, making it compatible with all standard 1.25" astronomy filters, such as moon filters, light pollution filters, or colored planetary filters.

    How would I use the SVBONY SV135 to observe Jupiter with an 8" Dobsonian?

    The SV135 is perfect for this. You would start at the 21mm setting to easily find and center Jupiter in the wide 57° field. Once centered, you can smoothly zoom in towards the 7mm setting to increase magnification, allowing you to resolve details like the Great Red Spot and the main equatorial cloud bands without losing the planet from the field of view.

    Is the SV135 a good choice for viewing the Moon in a small 70mm refractor?

    Yes, it's an excellent choice for a "grab-and-go" lunar setup. At 21mm, you can frame the entire full Moon within the field of view. You can then zoom in to any focal length down to 7mm to get dramatic close-up views of specific features like the Apennine Mountains or the crater Copernicus, all with a simple twist of the eyepiece.

    What is the main advantage of the SV135 zoom over a set of individual eyepieces?

    The primary advantage is convenience. Instead of carrying and switching between three or four separate eyepieces, the SV135 gives you every magnification between its 7mm and 21mm range in a single, 133g accessory. This allows for uninterrupted observing and the ability to perfectly match the magnification to your target and the current sky conditions.

  • Focal Length 7mm - 21mm
    Apparent Field of View 57° - 40°
    Eye Relief 18mm - 16.3mm
    Barrel Size 1.25"
    Optical Design 6 elements in 4 groups
    Coatings Fully Multi-Coated (FMC)
    Zoom Type Linear
    Filter Threads M28.5*0.6
    Rubber Eye Guard Yes
    Interpupillary Distance 15mm
    Construction Metal + Optical Glass
    Color Black
    Length 93mm
    Weight 133g / 4.67oz
  • SVBONY Warranty Policy