The 2x Barlow lens doubles the magnification with any given 1.25" eyepiece, without any noticeable loss in image quality.The large lens aperture allows you to use even very long focal length 1.25" eyepieces such as the TS Super Plossl 32 mm without vignetting. Multi-coated lenses and blackened lens edges result in optimum contrast and image sharpness. In our opinion the quality is en par with many much more expensive Barlows.
This 2x Barlow lens is particularly versatile:Visual Use - 2xJust insert the Barlow lens between the eyepiece and the telescope and you will double the magnification. At the same time you will retain the comfortable eye relief of the longer focal length eyepiece.
Visual Use - 1.5xJust screw the lens element of the Barlow lens directly into the filter thread of your eyepiece. The resulting magnification is reduced to about 1.5x.
TeleconverterJust screw the lens element of the Barlow lens into a 1.25" nose piece for your camera (e.g. TS FA 1). This turns the Barlow into a photographical converter with a factor between 1.5x and 2x (depending on the distance between lens and camera sensor).
Glass Path CorrectorBinoviewers require a long back focus distance that most telescopes do not provide. With the Barlow element you can move the focal plane further out, eliminating this problem in most cases. The effective magnification factor is about 2.6x with most binoviewers.
The TSB21-Barlow lens is designed in such a way that the Barlow element (i.e. the magnifying optics)
can be unscrewed from the holder. You can insert this element into the adapter
TST2-1-T2L. This adapter has the usual T2 thread on both sides, so the Barlow can easily be screwed between two T2 threads. This gives you the possibility to use the Barlow element also for astrophotography.