"While Barlows are powerful tools, the negative element defining them also limits their ability. The simple negative element Barlow increases eyepiece eye-relief. With short focal length eyepieces the effect is negligible. However, on long focal length eyepieces the exit pupil position moves well beyond the designer's intended position, resulting in vignetting with many eyepieces. This is why "Shorty" Barlows in particular, with their strong negative element often vignette and degrade long focus eyepieces. My 4-element form picks up where the Barlow concept can go no further. Powermate is a technically universal solution, using a positive field lens to redirect field rays. The result is an exit pupil that stays where the eyepiece designer intended. With freedom from aberrations, greater magnification potential, and compact size, I hope you'll agree Powermate raises the standard for image amplification." - Al Nagler
Pump up the power with Tele Vue Powermates. Powermates are ideally compatible with all eyepiece types, are optically "invisible" in the image, and are the best choice for photography when you want a larger image scale. They truly go where no Barlow has gone before.
Of course, Tele Vue touches such as full multi-coating, captive lock screw with brass clamp ring, complete baffling, and 100% quality control at f/4 ensure your satisfaction.
Tele Vue 2" Powermate in 4x Magnification
You can use this 4x Powermate to gain higher powers with typically long focal length 2" eyepieces. This Powermate requires far less refocussing compared to 2" Barlows when used in star diagonals. Weight = 1.20 lbs.
In addition to full multi-coating, Powermates include other Tele Vue special touches such as safety undercuts where practical on the chrome barrel, captive lock screws that can't fall out, and filter threads. Their 100% QC program at f/4 insures that Powermates will add dramatic power (and NOTHING ELSE) to your favorite eyepieces.
Powermates are the easiest method of increasing focal length for CCD and film photography. Each has been designed to accept optional adapters with T-ring threads. It's an attractive, high performance alternative to eyepiece projection.
Wolf359 New Member
- Skill Level
- Time with Product
Jan 31, 2008
- User Notes:
Build quality, optical quality, preserves eye relief.Cons:
Heavy, awkward to use due to length, expensive, possibly 3.8X mag factor.Comments:
I mainly got the 4X Powermate to use with my larger Nagler eyepieces and have (for the most part) been satisfied with its addition to my eyepiece case. It allows me to use my long focal length eyepieces at high powers while not drastically increasing their eye relief like a standard barlow. The Powermate is built like a tank and exudes quality from the moment you pick it up.
However, it does have a few drawbacks. First and foremost is its hefty weight which can cause balance issues on a Dob. Additionally, it's also quite long, causing your eyepieces to stick out quite a way from the optical tube, where they are easier to bump or knock around while moving about the scope. And from reading posts on forums around the web, the typical magnification factor may be closer to 3.8X than 4X for most eyepieces (I have not verified this yet from personal use).
Overall optical performance was excellent, but I did find some quirks when using with my longer eye relief eyepieces. Eye placement became more difficult and I had to back away more from the eyepiece to avoid blacking out. At first, I was concerned that the Powermate was not actually retaining the native eye relief of my eyepieces. But after some use I realized that it was more likely a result of trying to keep my eye placement with a much smaller exit pupil. In the case of my 26mm T5 Nagler without the Powermate, I would typically view with half of the eyecup folded down. However, using the Powermate, I found it difficult to use unless I kept the entire eyecup up. Similarly, with my 17mm T4 Nagler, I was used to viewing with the adjustable cup at three clicks out, but with the Powermate, I preferred 4 clicks instead. In each case, the eyepiece was easy to use after the slight change in distance and I did not lose any of the apparent field of view.
Overall, I would highly recommend the Powermate as an excellent way to increase the focal length options in a person's eyepiece collection, provided the weight and length are not an issue.Sort by