The series was introduced in 2007 and became popular quite quickly. A planetary eyepiece is an affordable atlernative to the popular but somewhat more expensive orthoscopic eyepieces. The original model was designed by the famous optician Thomas M. Back. The eyepieces provide maximum contrast and excellent image quality. The bigger field of view, the larger lenses and the eye relief makes it more comfortable for astronomical observations.
* 20 mm lens (easy to find where to see)
* 16 mm eye relief
* 58 degrees of field
* focal length is printed with large number on both sides (easy to find the correct one in darkness)
* rubber shield
* upper part can be extended to 16mm for comfortable observations
* 1.25" barrel
The Sky-Watcher Planetary eyepiece is a modified Plossl eyepiece with 5 lenses in 3 groups (or 6 lenses in 4 groups in the 9mm model), with all surfaces fully multi coated. Minimum distortion at the edges even in fast (f/5 or faster) scopes.