Tele Vue Powermate Concept User Manual

THE TELE VUE POWERMATE CONCEPT

- taming the Barlow to unleash its power

NOTE: For 35mm photography or CCD imaging, POWERMATES are ideal
alternatives to "eyepiece projection". For 1¼" Powermates (2.5X & 5X), unscrew

the bottom portion of the black barrel, thread it onto the special Powermate 1.25”

T-Ring adapter and screw it into your camera’s T-ring adapter. For 2” 2X
Powermate, unscrew the chrome barrel, thread it into the special Powermate 2X
T-Ring Adapter, and screw it onto your camera’s T-Ring adapter. For 2" 4X
Powermate, unscrew top half of black barrel and thread on the 4X T-Ring adapter.

Thank you for purchasing a POWERMATE: 1¼" (2.5x or 5x) or 2" (2x or 4x).
I thought you might be interested in the development of this project:
Barlows amplify the power of a telescope. They can be considered "focal reducers"

for eyepieces, or "focal extenders" for objectives.
Terence Dickinson, in his Barlow test report in Sky and Telescope, July 1997, says: "Technology has erased the

old objections. A modern Barlow will not degrade your telescope's optics. Anyone telling you otherwise is using
outdated information. Moreover, the highly regarded Nagler eyepieces and their clones have built-in Barlows,
ample evidence that the lens is not some detrimental intruder." Thanks, Terence, for laying the myth of the
degrading Barlow to rest.

Barlows do more than just increase magnification; they also retain eye relief (or in the case of long focal length
eyepieces, actually INCREASE eye relief). A high quality Barlow must be properly designed and manufactured
in order to avoid compromising a telescope's color correction and spherical aberration correction. The
"invisibility" of Tele Vue's 2-element Barlows have been noted in test reports in the astronomy magazines.

Barlow lenses, regardless of the number of elements, have negative power that diverge field rays. If Barlows are
made too short or with too much magnification, the diverging rays can cause severe vignetting and image
degradation in eyepieces due to mismatched pupils. I had to go beyond the simple Barlow concept to achieve
the goal of a compact, high power, fully corrected image amplifier.

Enter POWERMATE: My approach yielded a 4-element parfocal, compact amplifying lens system.
POWERMATE consists of a negative achromatic doublet plus a positive "pupil-correcting" doublet. While it looks
and functions like a Barlow, your eyepiece will operate with pupil locations where the designer intended, avoiding

mismatch problems. POWERMATE optimally mates its power to your eyepiece. No additional “interface lens” is

needed, since POWERMATES have it built-in.
In addition to full multi-coating, POWERMATE includes other Tele Vue special touches such as a safety

undercut on the chrome barrel where practical (2x and 2.5x POWERMATES do not insert fully on certain
diagonals) and captive lock screws that can't fall out. Our 100% QC program at f/4 insures that POWERMATE
will add dramatic power (and NOTHING ELSE) to your favorite eyepieces. If, for example, you own a 22mm
Panoptic, you’ll have the power of an 11mm focal length eyepiece (with the 2x Powermate), an 8.8mm focal
length eyepiece (with the 2.5x POWERMATE), a 5.5mm (with the 4x POWERMATE), or a 4.4mm (with the 5x
POWERMATE)!

Both 1¼” POWERMATES are constructed to be parfocal with Tele Vue’s 1¼” 90º diagonal (often used in smaller
telescopes) adding convenience not previously available with any Barlow. The 2.5x and 5x POWERMATE are
threaded for 1¼” filters.

I hope you enjoy your new POWERMATE. If you have any interesting experiences with it, kindly drop me a note
at your convenience.

For Dobsonian/Newtonian owners using Tele Vue’s Visual Paracorr coma corrector and a POWERMATE

• 1¼" POWERMATES (2.5x or 5x): Insert the 1¼" POWERMATE into the Paracorr’s 2"-1¼" adapter and set the
Tunable Top at its highest position.

• 2" POWERMATES (2x or 4x): Insert the 2" POWERMATE into the telescope’s 2" focuser, then insert the

Paracorr into the POWERMATE.
Please note that using heavy 2" eyepieces with the 2x or 4x POWERMATE could result in size and weight

combinations which may make it difficult to achieve proper balance on smaller instruments.

Clear skies,

Al Nagler, CEO

Tele Vue Optics, 32 Elkay Drive, Chester, N.Y. 10918 [phone]

POWRMAT13.doc 9/24/2013