Tele Vue 4.0x 2" Powermate (PMT-4201)
Al Nagler’s new 4-element concept, continues the tradition of full-field sharpness with optimum aberration control. Like long eye-relief? Retain the eye-relief of long focal length eyepieces, while at high power. Enjoy, for example, the sharpness and comfort of the 32mm Plössl at up to 5 times the power!
Unique Benefits and Applications for Powermates
- Vignetting, edge field aberrations and pupil movement - all introduced when using Barlows with long focal length eyepieces, are minimized.
- 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.
- High performance for image amplification, CCD or film (some of the finest Earth-based planetary imaging is being done with Powermates— see below).
- 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).
- Higher magnifications are possible with high optical performance compared to "doubling up" Barlows.
- All will reach parfocal point in star diagonals, except for the 2", 2x which comes very close.
In addition to full multi-coating, Powermates include other TeleVue special touches such as safety undercuts where practical on the chrome barrel and captive lock screws that can't fall out, and filter threads. Our 100% QC program at f/4 insures that Powermates will add dramatic power (and NOTHING ELSE) to your favourite eyepieces.
If, for example, you own a 24mm Panoptic, you'll have the power of a 12mm focal length eyepiece with the 2.0x Powermate, 9.6mm with the 2.5x Powermate, a 6mm with the 4x Powermate, or a 4.8mm with the 5x Powermate!
Imaging the Solar System with Powermates
Some of the finest Solar System images have been made with Powermates. Used singly or stacked, Powermates help any scope achieve the long focal-length required to image details on Solar System bodies. The increased image scale allows for imaging without an intervening eyepiece -- like in prime focus photography. Powermate T-Ring Adapters fit on the Powermate lens assemblies to allow attachment of your camera's T-Ring or other T-threaded imaging accessory.
Powermate Magnification Chart for Imagers
For astro-imagers, the above chart indicates the magnification for each Powermate (2x, 2.5x, 4x & 5x) as a function of distance from the Powermate eyepiece holder top surface to the imaging surface (CCD or film). (Imaging through a DSLR with the Powermate T-Ring Adapter and camera T-Ring — without added extensions — brings the focus position to 0mm.)
1.25" Powermates: 2.5x & 5x
These models stand less than 3" out of your focuser and both are threaded for 1.25" filters. They are parfocal in ALL 1.25" diagonals and prisms. For this reason, they are highly recommended over standard Barlows for 1.25" diagonals and refractors such as the TeleVue-60.
The 5x Powermate is ideal for long focus CCD and film photography, magnifying about 7.7x. It's an attractive, high performance alternative to eyepiece projection. The 5x is also perfect for slowing down your scope for Hydrogen-Alpha solar observing.
2" Powermates: 2x & 4x
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 we make (yes, even the 31mm Nagler Type 5!). Both the 2" eyepiece holder and the special 2" flat top adapter use our 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.
Note for Dobsonian/Newtonian Owners
When using TeleVue's Paracorr coma corrector, the 2.5x or 5x Powermate should be inserted into the Paracorr's 1.25" adapter (i.e., between the Paracorr and the eyepiece). For 2x and 4x 2" Powermates, first insert the Powermate into the focuser, then the Paracorr into the Powermates.