12mm 42° This unique measuring and crosshair eyepiece has an almost inexhaustible range of applications. The reticle has a 360 degree scale for measuring angular positions and distances of double stars, a scale divided into tenths of a millimeter for measuring planetary diameters, lunar craters and their shadow lengths and much more. The fine laser etching of the micrometer scale on the measuring plate allows line thicknesses of only 15 microns and line spacing of only 50 microns! This means that even smaller guide stars can be used and held well between the lines.