GSO 1.25" 3x ED Barlow Lens

Our Price: $40.00
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Our Product ID: OBAR-GS-GS3BL
Manufacturer SKU: GS3BL
Item Can Ship: Worldwide
GSO 1.25" 3x ED Barlow Lens

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Quick Overview

  • GSO's 1.25" 3x achromatic Barlow triples the magnification of each eyepiece and effectively doubles the number of eyepieces at your disposal
  • Full unit increases magnification of an eyepiece by 3x while maintaining a bright, high-contrast image
  • Air-spaced, two-element, fully-multicoated ED lenses with excellent color correction, sharpness, and image brightness
  • Precision-machined aluminum barrel with high-quality black-anodized finish

Product Details

GSO's 1.25" 3x ED Barlow is the perfect choice when you need more magnification than the common 2x barlows will provide. This barlow uses two-element, fully-multicoated lenses made from special ED (Extra-Low Dispersion) glass for excellent color correction and sharpness. The clear aperture is 24mm and the lower end of the barlow cell is threaded to accept standard 1.25" filters. The body is precision CNC-machined from aluminum and sports a handsome finish that you would usually find on much higher priced items.

You can unscrew the barlow element and use the upper tube as a 1.25" extension tube to provide 79mm (3.11") of extension . However, because the upper end of the 3x barlow cell (that connects to the barlow tube) uses a non-standard thread, you cannot attach the barlow element directly to other eyepieces like you can do with the GSO 1.25" 2x barlow.

Note that the use of any optical element like barlows and focal reducers changes the focus point of your telescope, requiring additional in-focus or out-focus travel. The exact amount of focus travel required will depend on the optics and mechanics of your specific set-up (telescope, diagonal (if used), barlow, and eyepiece). Hence, be aware that you may not be able to reach focus with all eyepieces or in all configurations with a given barlow.


  • Barrel Size: 1.25 inch (31.7mm)
  • Magnification Factor: 3x
  • Coatings: Fully multicoated
  • Weight: 4.3oz
  • Height (Total): 126mm
  • End Caps: 2
  • 1.25" filter threads on bottom of barlow: Yes
  • Made in Taiwan
Manufacturer GSO
Size Format 1.25 inch
Magnification Factor 3x
Number of Lens Elements
Lens Coatings Fully multicoated
Total Length 4.96 inches / 126 mm
Length of Nosepiece 2.09 inches / 53 mm
Outside Length of Upper Body 2.92 inches / 74.1 mm
Insertion Depth 1.61 inches / 41 mm
Max Diameter Excluding Thumbscrew 2.19 inches / 55.7 mm
Clear Aperture 0.94 inches / 24 mm
Weight 4.3 oz / 122 g
Barlow Lens Cell Removable Yes
Filter Threads at Bottom of Barlow Cell Yes - 1.25" (M28.5x0.6) Filter Threads
Filter Threads Between Barlow Cell and Tube Non-standard Threads
Barrel Type Smooth-sided
Compatible Agena Bolt Case (with Screw Removed) 42x80
Compatible Bolt Case (with Screw Attached) 52x80
Number of Thumbscews 1
Thumbscrew Thread Specification M4x0.7
End Caps (Subject to change without notice) 2
Compression Band/Ring in Eyepiece Holder No
Country of Manufacture Taiwan