Binorum Optima 2x Achro T2 1.25″ Barlow Lens
The Binorum Optima 2x Barlow lens is a universal optical accessory designed for both visual observation and astrophotography. This achromatic multiplier doubles the effective focal length of your telescope, allowing you to achieve higher magnification without the need to purchase additional eyepieces.
How the Barlow Lens Works
A Barlow lens is a diverging optical system placed between the telescope and eyepiece (or camera). It extends the effective focal length of the telescope, thereby increasing the resulting magnification. A 2x multiplier means that a 10mm focal length eyepiece will provide the same magnification as a 5mm eyepiece without the Barlow lens, while maintaining more comfortable eye relief and a wider field of view.
This characteristic is particularly valuable in planetary observation, where you need high magnification to study fine details on Jupiter, Saturn, Mars, or the Moon. Instead of investing in expensive short focal length eyepieces, you can double the magnification of your existing eyepieces with a single Barlow lens.
Achromatic Optical Construction
The Binorum Optima Barlow lens utilizes an achromatic optical design consisting of multiple elements that minimize chromatic aberration - color fringing around bright objects. This provides sharp, high-contrast images with accurate color rendition, which is crucial for observing planets and the Moon, where seeing true colors and fine details is important.
Visual Observation
For visual use, simply insert the Barlow lens into the 1.25″ focuser of your telescope or diagonal, then thread the eyepiece into the output end of the Barlow lens. You immediately gain double magnification with all your 1.25″ eyepieces.
This flexibility allows you to effectively double your eyepiece collection - if you have, for example, 25mm, 15mm, and 10mm eyepieces, with the Barlow lens you effectively also gain 12.5mm, 7.5mm, and 5mm equivalents. This provides a wider range of magnifications for different observing conditions and targets, without needing to invest in a complete new set of eyepieces.
Astrophotography with T2 Threading
On the output side, the Barlow lens is equipped with T2 threading (M42x0.75) for direct camera attachment using the appropriate T-ring specific to your camera brand (Nikon, Canon, Sony, etc.). This feature makes the Binorum Optima Barlow lens an excellent choice for planetary astrophotography and lunar imaging.
Doubling the focal length increases the image scale, meaning the planet or Moon occupies more pixels on your sensor. This is crucial for capturing fine details - larger image scale allows you to record structures in Jupiter's atmosphere, details in Saturn's rings, or craters on the Moon with higher resolution.
For astrophotography, simply unthread the eyepiece and replace it with a camera attached via T-ring. The Barlow lens remains inserted in the telescope focuser and extends the focal length to achieve the desired image scale.
Use as a T2 Adapter (Optical Length 35 mm)
The optical element of the Barlow lens can be unscrewed. After its removal, the housing can be used as a T2 photo adapter with an optical length of 35 mm (1.25″/T2) without magnification.
Universal Compatibility
The standard 1.25″ barrel diameter ensures compatibility with most astronomical telescopes, eyepieces, and accessories. The Barlow lens works with refractors, Schmidt-Cassegrain telescopes, Maksutov-Cassegrain systems, and Newtonian reflectors equipped with 1.25″ focusers.
Quality Construction
The robust metal body protects the optical elements and provides precise threading for secure attachment of eyepieces and T-rings. Precisely machined components maintain proper optical alignment, which is critical for preserving image sharpness at high magnification or during long photographic exposures.
Practical Advantages
The Barlow lens represents an economical solution for expanding your telescope's capabilities. Instead of purchasing several expensive short focal length eyepieces for high magnification, you can effectively double the utility of your existing eyepiece collection with a single Barlow lens. For astrophotographers, it provides a flexible tool for adjusting image scale without needing to change telescopes.
