Powermates are the highly-evolved answer to the Barlow lens design from Tele Vue.
While barlow lenses increase the eye relief of the eyepiece in use, they also reposition the exit pupil of long focal length eyepieces far from the designer's intended position. This can cause vignetting and image degradation.
Using four elements, the Powermates leave the exit pupil where it was intended to be, restoring the full viewing aperture and optical quality of long focal length eyepieces. Have the best of both worlds; the long eye relief of the longer focal length eyepieces, but with higher magnification!
Nearly parfocal with 2.00" diagonals, the 2.00" Powermates are threaded to accept 48mm filters and their performance is exemplary with every 1.25" & 2.00" eyepiece in the Tele Vue line.
Directly accepts all 2" eyepiece
Threaded for 48mm filters
Works well with diagonals, unlike many normal Barlow lenses
Accepts optional PTR-2200 SLR camera adapter (imaging w/o eyepiece)