Powermate V's Barlow

[LukeSkywatcher]

I was doing some reading today about Powermates and i have to say that even i was seduced by the write up on them compared to Barlows.

From what i read the powermate seems to pick up where the Barlow left off, with respect to magnification and quality of image.

Apparently the Barlows pitfall is the "negative" lens inside. The lens in powermates are all "possitve".

I recently bought a TAL 2x Barlow and i have to say that i am delighted with its performance. It really is a great performer for the price tag.

I'm slowly starting to understand/appreciate the difference between quality(ish) optics (EPs etc) and poor quality optics.....mainly by splashing out a BIT more on single EPs (£30 on a 30mm Vixen and €55 euro on a 4mm Omni in the last week).

I'm now starting to think that a 2X powermate (new or SH) could be worth an investment given the respect and good name that TV optics have and seeing the difference in quality that spending a few quid more gets you.

So basically i am just looking for opinions,comments etc on Powermates,experience of (good and bad), and likewise on Barlows.

A discussion of Powermate V's Barlow basically is what i am after.

[johninderby]

Al Nagler himself says that for a scope that doesn't use a diagonal, such as a newt, the barlow is just as good as the powermate. The powermate was designed for scopes using a diagonal where it corrects for problems caused by the diagonal.

John

[John]

Hi Paul,

I had a TAL 2x, then a Celestron Ultima 2x and then a Powermate 2.5x. Each was a step up in terms of optical performance (though the TAL is very good for it's cost) but the Powermate was the first "amplifier" that I've tried that truly "got out of the way", ie: had no impact on image quality that I could detect, apart from the extra magnification.

The only similar thing that I've tried in the 2" fitting was a Meade TeleXtender 2x which is a similar concept to the Powermate. That was also very impressive athough I found the 2" format, coupled with my 2" diagonal an heavy eyepieces was just a bit too much for comfort.

What I really liked about the Powermate was that the focus position of the eyepieces it was used with did not change (you always seem to loose some in-focus travel with the short format barlows I've tried) and the eyerelief stays the same as the native eyepiece (barlows extend the eye relief which can be good but can also make finding the correct eye position difficult).

So that's my findings - hope that helps a bit

Noting John's comment, my experience was with refractors.

[LukeSkywatcher]

What I really liked about the Powermate was that the focus position of the eyepieces it was used with did not change (you always seem to loose some in-focus travel with the short format barlows I've tried)

Yes exactly. That seems to be the MAIN reason people prefer Powermates over Barlows.

Al Nagler himself says that for a scope that doesn't use a diagonal, such as a newt, the barlow is just as good as the powermate. The powermate was designed for scopes using a diagonal where it corrects for problems caused by the diagonal.

That's interesting. Nowhere did i read that Powermates were designed for scopes that use diags (that would mainly be refracs?).

As i said......i am not looking to be convinced about buying a Powermate. I'm just interested in them and who better to ask then those who know about them.

[johninderby]

Managed to find one Al Nagler quote as below.

" You didn't say what type of scope you have. If you called Tele Vue, We would have recommended the Big Barlow if you have a Newtonian, and the powermate if you have a refractor. The reason?,

For the Nagler eyepieces the optical benefits of the powermate are invisible, however, ergonomically in a Newtonian both the BB and powermate will reach their parfocal point.

In a refractor, where a diagonal is used, the BB will not come close to reaching it's parfocal point, and an inch or so of in-travel will be required. "

John

[Chris H]

For use with medium to short focul length ep's the change in eye relief caused by a barlow is minimal maybe an extra mm or so, so it's not really noticeable. If you are going to barlow a long focul length ep for example a 30mm then the change will be greater and you may find a powermate would be the answer.

I have used a Televue x2 and x3 barlow with the heritage both worked superbly. I have now sold them and am currently using a Televue x2 BIG barlow (I only use 2" ep's) with my XT10i and it is excellent I'm very glad I didn't spend the extra on a x2 Powermate. I barlow my 12mm, and 8mm ep's nothing longer.

[great_bear]

The other thing PowerMate's correct for is vignetting. Normal Barlows - particularly short ones - tend to cut off the nice crisp viewing circle of an eyepiece, leaving a fuzzy edge instead. I sent back my Celestron Ultima Barlow back to FLO for refund for that reason alone.

[brianb]

I have now sold them and am currently using a Televue x2 BIG barlow (I only use 2" ep's) with my XT10i and it is excellent I'm very glad I didn't spend the extra on a x2 Powermate.

Interesting .... I've had a TV X2 BIG barlow & found it possibly the worst barlow I've used in a long time (distortion, chromatic aberration). I now have a TV 2x Powermate & it's excellent.

The real difference with the Powermates (apart from the x5) is that the magnification is pretty well independent of the position of the focal plane. This is a big help when imaging. A "2x" barlow used with a webcam is probably nearer 3x because of the extra extension caused by the sensor being embedded deep in the lump. Also there is next to no distortion with Powermates.

[Chris H]

Interesting .... I've had a TV X2 BIG barlow & found it possibly the worst barlow I've used in a long time (distortion, chromatic aberration).

When I was researching the BIG barlow I came across a number of negative reviews on cloudy nights and I started to lean towards the powermate. I then PM'd a number of people who use them with newtonian's and got nothing but good reports, finally I contacted Paulo on this site he was also liked the big barlow so I went for it thinking if I don't like it I can sell it. So far so good.

[great_bear]

if I don't like it I can sell it. So far so good.

That's the best thing about the second-hand market

Sometimes with bad reviews about stuff there's just a QC issue and the basic design is good.

[Moonshane]

That's the best thing about the second-hand market

Sometimes with bad reviews about stuff there's just a QC issue and the basic design is good.

totally agree with this too - it's the main advantage for me of buying used good quality gear - you often get back what you paid.

re Powermate Vs. Barlow, I used a few barlows for a while (although admitedly with poorer quality eyepieces) and was never really happy with the views. I still have a 2x Cape Instruments Barlow and will try and undertake an objective review sometime - if the clouds ever clear up!

As a result of reading various excellent reports on the 1.25" 2.5x Powermate, I bought one and was instantly hooked. It really makes it like you have a second string of eyepieces with the same eye relief and quality of image for both. The only degradation is what you'd expect normally with increased magnification due to smaller exit pupil and seeing etc.

A used Powermate (maybe £100) is about £30 more than a new Celestron Ultima barlow and personally, I'd never consider anything other than a Powermate. It just oozes quality.

If you buy a used one, make sure it's the compression ring version.

I also use mine in the dob and my refractor and it's excellent in both. I don't think there's a reason not to use one in a Dob, it's just that your parfocal eyepieces may not be parfocal anymore. For me, as a visual only observer, it's not a big issue to refocus slightly after changing eyepieces. Personally, I'd sooner retain the original eye relief of the eyepieces used.

[Rossco72]

I am fortunate enough to have the full suite of powermates and will never use a barlow again.

I have a 2x televue barlow for nostalgic reasons and its excellent but its just not in the same league as the powermates.