A part of their Astro T-2 line, the Alpine Astronomical Baader Polaris I 25mm Illuminated Measuring and Guiding Eyepiece is an ideal companion piece for improved tracking accuracy and measuring the size and magnitude of celestial objects.
The 25mm focal length produces a relatively low power on most telescopes to ensure a generous 40° field of view, while the 3-element/2-group lens design and Phantom Group multi-coatings ensure bright, clear, and crisp views. A double-cross reticle displays across the entire field of view and is illuminated red to preserve night-adjusted vision. To ensure the perfect amount of brightness, a rheostat gives users 11 intensity levels.
Internal threads on the front allow it to be directly attached to Astro accessories such as diagonals, or users can add optional 1.25" or 2" nosepieces for use as conventional eyepieces. On the back end is a fold-down rubber eyecup that can be removed to reveal standard T-mount threads. These accept optional camera-specific T-rings for various astrophotography and imaging techniques.