What's the best Barlow

[vince 66]

I'm always looking to squeeze that little bit extra from my scopes so rather than spend a small fortune on a 3 to 4 mm eye piece. Does anyone use a Barlow and what type. My eye pieces are Pentax XW s. So I would be looking for a Barlow that would compliment their performance.

[John]

Hi Vince

I've used Tele Vue Powermates with my Pentax XW's and they are really excellent. No quality seems to be lost at all, you just get the amplification.

The Explore Scientific Focal Extenders are also very good.

These devices are more complex optically than barlow lenses but have the same function. They tend not to affect the eye relief (barlows extend it) though and the focal point remains close to where it originally was.

[Charic]

Have you considered a TeleVue Powermate? http://www.televue.com/engine/TV3b_page.asp?id=53&Tab=_back#.Vj_eZLfhCJA

.....I obviously type too slow! John beat me to it.

[Highburymark]

TeleVues always mentioned in best Barlow discussions but Baader VIP considered to be optically excellent and very adaptable

[knobby]

If you're on a budget then a Revelation Astro 2.5 x is pretty good too

[Mak the Night]

I don't think you can go wrong with the TeleVue 2x, 3x Barlows and the TeleVue Powermate. 

This TV 3x was the first quality Barlow I ever bought, I've never regretted it.

[John]

Theres an Astro Physics Barcon on UK Astro Buy & Sell

[alan potts]

Like John I have used Powermates but have now sold them on, not that there was anything wrong with them, I just seemed to use them to get short F/L Ethos effects when I had perfectly good Delos eyepieces covering those bases. I have also used Meade tele-extenders and they are very good as well.

[niallk]

I have a 2.5x Powermate - it is superb - just amplification; no other discernable effects to my untrained eye.

If I was buying again, I might have considered the 2" 2x PM with 1.25" insert as the best investment.

I also find the PM effective when binoviewing - working in my 15" where a 2.5x GPC failed to allow me to reach focus. I don't know but suspect that the telecentric nature of the PM worked in my favour here.

[YKSE]

Theres an Astro Physics Barcon on UK Astro Buy & Sell

I'd second that one or TMb Barlow 1.8x ED if you want to be sure of the best.

I also find the PM effective when binoviewing - working in my 15" where a 2.5x GPC failed to allow me to reach focus. I don't know but suspect that the telecentric nature of the PM worked in my favour here.

Isn't it a bit strange? A powermat shouldn't alter the focus point(or very lite), while a barlow pushes out focus point, which is of help for binoviewer to achieve focus.

[John]

I'd second that one or TMb Barlow 1.8x ED if you want to be sure of the best.

I've expressed an interest in both the AP Barcon and the above TMB Barlow over the past couple of years but despite the undoubtedly superb optics I'd not be able to be confident of bringing them to focus with my scopes. Both seem to require quite significant amounts of inward focuser movement. I even read a post by Roland Christen on a Yahoo group a couple of years back explaining why thats the case.

[niallk]

Isn't it a bit strange? A powermat shouldn't alter the focus point(or very lite), while a barlow pushes out focus point, which is of help for binoviewer to achieve focus.

Here was my reasoning:- could well be wrong

I had tried my Baader GPC, and was dismayed that I couldn't focus. I was thinking about it the following day: if a PM 'outputs' parallel rays (telecentric), then the distance shouldn't matter through the binoveiwer (say 11cm).

I tried it the next opportunity, and it worked. Happy coincidence or not, I'm happy - had detailed views of Jupiter in my 15" earlier this year.

[YKSE]

Niallk, I can't say that I follow your reasoning, but I'm glad it works for you.

[Dave In Vermont]

I don't think you can go wrong with the TeleVue 2x, 3x Barlows and the TeleVue Powermate. 

This TV 3x was the first quality Barlow I ever bought, I've never regretted it.

The photo in this post isn't showing, so I'll put it up:

And I too will suggest that for a Barlow, the TeleVue offerings in both 2X and 3X may be considered top-notch. They rather vanish in your optical-pathway. This is what you want from a good Barlow - they magnify the image without any dimming or degradation of the image quality of the object you're trying to view. I don't generally recommend TeleVue due to their higher cost, but make an exception with a Barlow. And their price isn't really too much more than others. So go ahead - put those elitist 'green-letters' in your eyepiece-case!

The PowerMates are a different animal, but for all intents and purposes I'll just say that they're absolutely excellent.

Enjoy!

Dave

[michael.h.f.wilkinson]

I would certainly recommend the PowerMate 2.5x I have. In 1.25" fitting I also have the Meade TeleXtenders in 2x and 3x, and they are every bit as good, I find. The advantage of the tele-centric design (rather than a simpler Barlow design) is that they tend to show no vignetting in SWA and UWA EPs. The Meade Series 5000 TeleXtenders are no longer sold, you could go for the Bresser SA Barlows (same things) or the Explore Scientific Focal Extenders (apparently same optics).

[rwilkey]

I have the ES 2x focal extender and confirm it works very well, exactly as John describes for the TV's, most pleased with it!

[Mak the Night]

I think if I had to answer: 'What is the best Barlow?' I'd probably have to say the 2.5x Powermate, although it's not a true Barlow in the strict sense, it's one of my most used eyepieces. So it was well worth the ridiculous amount of squid I parted with for it! lol