The lens assembly consists of a triplet-element and one plano-convex eye lens, so there are only four glass-air-surfaces. The interior has been blackened for a very good suppression of stray light. Of course, the hard anodised barrel has got a filter thread.
Looking into the eyepieces, you'll see the effect of the anti-relex-coating and the blackened lens edges. The coating is so good that it seems like there are no lenses at all! On our optical bench, we couldn't find any disadvantages compared to so-called "planetary eyepieces" which cost five times more.
The eyepieces use the same glasses and the same optical design as the old orthoscopic Zeiss Jena eyepieces.
The 32mm-Plössl-eyepiece is the perfect eyepiece for a large field of view at telescopes with 1,25"-focuser; eyepieces with longer focal lengths don't provide a larger field of view (but a smaller apparent field).
Focal length (mm) | Optical design | Barrel | Lens elements / groups | Apparent field of view | Parfocal | EyeRelief (mm) |
Field stop (mm) | Height (mm) | Diameter | Weight |
---|---|---|---|---|---|---|---|---|---|---|
6 | Classic Ortho | 1¼" | 4 / 2 | 52° | yes | 5 | 5 | 34,2 | 34,8 | 37g |
10 | Classic Ortho | 1¼" | 4 / 2 | 52° | yes | 8 | 8,7 | 41,12 | 34,8 | 48g |
18 | Classic Ortho | 1¼" | 4 / 2 | 52° | yes | 14,67 | 16,8 | 54,46 | 34,8 | 81g |
32 | Classic Plössl | 1¼" | 4 / 2 | 50° | yes | 21 | 26 | 78,8 | 34,8 | 94g |