Tele Vue Powermate линза 2.5x

Concept: Barlow lenses, based on a negative optical element, have certain limitations in their field of application and also introduce certain changes in the characteristics of the entire optical system. For example, a single negative lens significantly extends the exit pupil of the eyepiece. With short focal length eyepieces, the effect is negligible, but with long focal length eyepieces, the pupil can shift much further than intended in the eyepiece design, leading to vignetting and image quality degradation in many cases. The new 4-element optical design allows access to places where classic Barlow lenses typically become useless. The Powermate, a functional equivalent of the Barlow, is a versatile design made using converging lenses. Its use does not affect the exit pupil distance. – Al Nagler The new 4-element design created by Al Nagler perfectly matches TeleVue's fidelity concept. Using uncompromising solutions, it is possible to obtain ideally sharp, aberration-free images across the entire field of view. Unlike standard Barlow lenses, this design does not change the exit pupil distance and does not cause vignetting. This opens up entirely new possibilities. Imagine the brightness and convenience of a 32mm Plossl eyepiece, which, thanks to the Powermate 5x lens, behaves like a planetary eyepiece with a focal length close to 6mm. For Powermate and Barlow lenses. To understand how Powermate lenses work, we need to understand how classic Barlow lenses work. A Barlow is an element that increases the magnification of a telescope. It can be considered a reducer of the eyepiece's focal length or, conversely, an element that extends the telescope's focal length. Modern Barlow lenses designed for specific eyepiece series not only do not degrade the resulting image but also optically complement these eyepieces. A high-quality Barlow lens must be properly and thoughtfully designed. Otherwise, additional chromatic and spherical aberration may occur in the telescope's optics. Tele Vue Barlow lenses are among the best - it is enough to mention that readers of astronomy magazines call them "invisible" lenses. The properties of the negative element, which is the heart of the Barlow lens, determine not only the change in the scale of the resulting image but also several other optical effects. The most noticeable property of negative Barlow lenses is their effect on the position of the exit pupil of the attached eyepiece. At short and medium focal lengths, the increase in distance is barely noticeable. The situation becomes somewhat inconvenient when we have to combine a Barlow eyepiece with a long focal length eyepiece. Then the pupil moves far away from the eyepiece, observation becomes uncomfortable, and vignetting becomes a serious problem. When we introduced Powermate lenses to the market, we overcame previous limitations. A compact and well-corrected magnification converter has been created. Optically, it is a 4-element system, grouped into two doublets. The first doublet consists of two negative lenses, the second doublet, which is intended to... correct the influence of the diverging lenses on the exit pupil, consists of two converging lenses. Advantages of using Powermates™ lenses – Reduced vignetting, edge aberrations, and off-axis aberrations characteristic of classic Barlow lenses. – The Powermate optical system creates a flat image at the focal plane. The direction of light rays does not depend on the distance from the optical axis and is parallel to each other. This positively affects observations in narrow spectral bands (e.g., H-alpha). – High optical quality, sufficient for astrophotography. – Powermate is suitable for all types of telescopes. It does not affect the focal plane, it is parfocal. Except for the 5x model, the image scale does not depend on the distance between the lens and the light detector. – Due to higher optical perfection, we can achieve higher maximum magnification than when using eyepieces with traditional Barlow lenses. – Except for the 2-inch 2x model, all Powermate lenses work correctly with diagonals. Photography of Solar System bodies using Powermates™ lenses. Many amazing photos of Solar System bodies have been taken using Powermates lenses. Without significant loss of quality, you can increase the telescope's focal length to the level required for planetary observations. Powermates lenses can be combined into sets, where the system's magnification is the product of the component magnifications. This is enough to achieve a scale where the eyepiece is no longer needed for projection. Technical data: | frame: 1.25 inch