Baader 1.25" Classic Ortho 6mm (HT-mc) Eyepiece - original Zeiss Ortho design. We recommend the Baader Classic Orthos to all observers who value a bright image with optimal sharpness on-axis. These eyepieces are particularly suitable for planetary observation and photography, eyepiece projection, double star observation, as well as for viewing deep-sky objects where a large field of view is not a priority. Classic orthoscopic eyepiece design according to Ernst Abbe's construction, providing a completely distortion-free image, 1.25" barrel without safety notch. The Baader Classic Orthoscopic Eyepieces are parfocal - no adjustment of focus is necessary. Focal length: 6mm, barrel diameter: 1.25" without safety notch, apparent field of view: 52°, field stop diameter: 5mm, eye relief: 5mm, weight: 37g.