These Powermates are a better choice for 2" diagonals than Barlows, since they are nearly Parfocal. They are threaded for 48mm filters and their performance is excellent with every 1.25" and 2" eyepiece Tele Vue make (yes, even the 31mm Nagler Type 5!). Both the 2" eyepiece holder and the special 2" flat top adapter use Tele Vue's brass clamp rings for secure operation. And, it also has a very unique feature: you can unscrew the 2" eyepiece housing and screw on a special T-ring adapter for solid, compact attachment of CCD or camera equipment.

Excellent with long eye-relief, 2" eyepieces. Using the 4x model, imagine the quality of a 35mm Panoptic at 8.8mm with 25mm of eye relief! The Powermate is NOT a Barlow so the Panoptic-Barlow Interface is NOT needed! The 2" Powermate fits all the way into 2" Star Diagonals, requiring minimal refocus compared to a 2" Barlow. 

           Unique Benefits and Applications for Powermates™

1. Vignetting, edge field aberrations and pupil movement - all introduced when using Barlows with long focal length eyepieces, are minimized.
2. Telecentric operation (field rays leave parallel to optical axis, unlike Barlow lenses which diverge rays). This is ideal for Hydrogen-alpha filter use such as with Daystar models.
3. High performance for image amplification, CCD or film (some of the finest Earth-based planetary imaging is being done with Powermates™ -- see below).
4. Flexible for visual and imaging with all types of telescopes and eyepieces. Essentially Parfocal, and with nearly constant magnification regardless of image distance behind top surface (except 5x model which increases 1x for every 35mm of image distance increase).
5. Higher magnifications are possible with high optical performance compared to “doubling up” Barlows.
6. All will reach parfocal point in star diagonals, except for the 2”, 2x which comes very close.

 Specification :

- Barrel : 2"
- Weight 1,2 lb