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GSO 2.5x Achromatic 3-Element Barlow ( 31.7mm, 1.25 )

GSO 2.5x Achromatic 3-Element Barlow ( 31.7mm, 1.25 )
GSO 2.5x Achromatic 3-Element Barlow ( 31.7mm, 1.25 )
Ex Tax: £33.25
  • Stock: 9
  • Model: B25apo
  • Shipping Weight: 0.16kg
  • SKU: B25apo
  • GTIN: 0702403404200
  • MPN: B25apo
  • Location: C6

GSO 2.5x Achromatic 3-Element Barlow ( 31.7mm, 1.25 )

This is one of our bestselllers due the combination of high quality and comparatively low price...

Its 2.5x maginifaction is a good choice for telescopes where a 2x Barlow would be not enough, but a 3x version is an overshoot...

Although it is presented as a 2.5x achromatic Barlow lens, however note, its quality is closer to a real APOCHROMATIC BARLOW as combines three optical elements .

The aim of Barlow lenses is to prolong the telescope's focal length, so e.g. with a 2x Barlow, when we divide the doubled focal length of a telescope with the focal length of the eyepiece we got twice the magnification obtained. This is a popular amateur complementary tool, because with the help of a Barlow lens we can achieve more diverse magnification range with the same telescope without having to obtain additional eyepieces. On the other hand, since the aperture is usually smaller and the eye relief is shorter for eyepieces with shorter focal length (higher magnification eyepieces), thus these are less comfortable, therefore with a Barlow we can achieve the same magnification but by using a more  comfortable (with a longer focal length) eyepiece. 
Barlows are so good that they are being used even in more expensive wide-angle eyepieces where the Barlow is simply integrated into the construction of the eyepiece.
The Barlow lens is always being used between the telescope lens and the eyepiece. Barlow lenses will fit a 31.7 mm or 50.8 mm eyepiece holder barrel.
This particular one will fit a 1.25" holder barrel.

Fully Multi-Coated
Size: 31.7mm, 1.25"
Field Stop: 23mm
Overall length: appr. 76mm
Length of 1.25" nosepiece: appr. 30.5mm
Optical path: appr. 46mm
It comes with brass compress ring for safe, scratch-free insertion of eyepieces.

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