GSO 1.25" 2.5x Apochromatic Barlow Lens # BL251

Our Price: $55.00
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In stock (10+ Available)
Ships by Next Business Day
Our Product ID: OBAR-GS-BL251
Manufacturer SKU: BL251
Item Can Ship: Worldwide
GSO 1.25" 2.5x Apochromatic Barlow Lens # BL251

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  • GSO 1.25" 2.5x Apochromatic Barlow Lens # BL251

Quick Overview

  • GSO's 1.25" 2.5x fully apochromatic Barlow increases the magnification of each eyepiece and effectively doubles the number of eyepieces at your disposal
  • Low profile maintains a comfortable viewing position
  • Air-spaced, three-element, fully-multicoated ED lenses with excellent color correction, sharpness, and image brightness
  • Precision-machined aluminum barrel with high-quality black-anodized finish and knurled ring to aid in handling

Product Details

If you need more power than your eyepieces alone can provide, we offer a new apochromatic 2.5x Barlow lens from GSO (Guan Sheng Optical) to give a big magnification boost to any 1.25" eyepiece it's used with.

Nothing has been compromised in GSO's latest and finest offering. This Barlow features an air-spaced, three-element, apo design with fully multicoated optics. The housing is precision machined from aluminum stock and black anodized to a hard finish. The lens edges and inner barrel are blackened to provide maximum contrast. The Barlow body includes a brass compression ring so that your eyepiece barrels are not marred by the captive set screw. The 2.5x model has a clear aperture of 23mm. For those who need a very high quality Barlow for all-round use, the 2.5x barlow is a very nice step up from the typical 2x achromatic barlows commonly found on the market.


  • Barrel size = 1.25" (31.7mm)
  • Magnification factor = 2.5x
  • Weight = 3.5oz (99gm)
  • Total height = 2.95" (75mm)
  • End caps = 2
  • 1.25" filter threads on bottom of barlow: No
  • Made in Taiwan
Manufacturer GSO
Size Format 1.25 inch
Magnification Factor 2.5x
Number of Lens Elements
Lens Coatings Fully multicoated
Total Length 2.95 inches / 75 mm
Length of Nosepiece 1.18 inches / 30 mm
Outside Length of Upper Body 1.8 inches / 45.7 mm
Insertion Depth 1.57 inches / 40 mm
Max Diameter Excluding Thumbscrew 1.92 inches / 48.8 mm
Clear Aperture 0.88 inches / 22.4 mm
Weight 3.5 oz / 99 g
Barlow Lens Cell Removable No
Filter Threads at Bottom of Barlow Cell No
Filter Threads Between Barlow Cell and Tube N/A
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 Yes
Country of Manufacture Taiwan

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