Designed for flexibility and versatility, the Alpine Astronomical Baader 2x VIP Modular Barlow Lens is built with modular pieces that allow it to be easily adapted for a wide range of visual and photographic applications with the easy addition of an array of optional adapters such as diagonals, T-rings, and extension rings. A seven-layer multi-coated, apochromatic field-flattening air-spaced lens design maximizes light transmission while improving contrast and clarity and correcting spherical aberration and astigmatism.
When used out of the box as a conventional Barlow, it doubles the magnification of any eyepiece that is put in it. It accepts 1.25" eyepieces and has a bronze locking ring to hold the eyepiece firmly in place without marking or marring it. The telescope side has both 1.25" and 2" barrels to fit into the two most popular-size drawtubes, focusers, and accessories without modification.
Beyond this out-of-the-box functionality, it was designed with a 24mm clear aperture for use on 35mm film cameras or full-frame DSLRs with 24x36mm sensors to avoid vignetting. The different components can be disassembled to allow photo T-rings, extension tubes, and eyepiece filters to be inserted for customized configurations depending on the application. Baader's Amici star diagonal can also be inserted into the Barlow for an integrated magnification within the light path. Any customization to the Barlow will probably require adding optional adapters for proper use.