Televue Big Barlow

[Damo636]

Is anyone currently using or has previously used the 2" Televue Big Barlow and what are your thoughts on its performance? I have the 1.25" version & find it superb and wondering how they compare?

Thanks guys!

[John]

I've not used one Damo but I've read quite a lot of reports on them over the years and to be quite honest they are somewhat more mixed than most Tele Vue products attract. 

I believe that TV themselves say that the Big Barlow is more suitable in certain scope designs than others but I can't recall which offhand. Worth doing some more research before committing I would think.

[Damo636]

Thanks John. Reviews are thin on the ground and indeed conflicting?? More research needed!

[Adrian Condon]

Hi Damo,

I have a Televue Big Barlow. I have found it fine with the eyepieces I have.

I believe that if you have Televue 27 & 35 mm Panoptics eyepieces you need a special adapter on the Barlow.

I mainly use mine with my Televue 55mm Plossl.

Before you spend your money, see if you can try one out. Is there an Astro Club in NI near you?

Cheers

Adrian

[Damo636]

Thanks for the feedback Adrian. Unfortunately there are no astro clubs nearby so trying one out not really an option. I think the adapter you refer to is the Panoptic Barlow Interface & it essentially converts the Big Barlow into a 2x Powermate.

I've managed to dig up this quote by Al Nagler on the Big Barlow vs Powermate..

" 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. "

So basically, (and I stand to be corrected here!), the 2x Powermate is basically the 2x Big Barlow with the interface fitted, and the only advantages it has over the BB is that the focus position is unchanged and the original eye relief retained??

[Naemeth]

Thanks John. Reviews are thin on the ground and indeed conflicting?? More research needed!

Perhaps they are thin on the ground because people prefer the Powermates - is there a specific reason you've gone for the Barlow over the Powermate?

[Damo636]

Perhaps they are thin on the ground because people prefer the Powermates - is there a specific reason you've gone for the Barlow over the Powermate?

Weight, cost, curiosity! I've owned the 2x Powermate in the past and it is indeed excellent, but I recently picked up a 1.25" Televue barlow and to be honest it has similarly impressed. The only thing I'm not that keen on, is using the 13/8mm Ethos in 1.25" mode (although it works flawlessly)

[Naemeth]

Weight, cost, curiosity! I've owned the 2x Powermate in the past and it is indeed excellent, but I recently picked up a 1.25" Televue barlow and to be honest it has similarly impressed. The only thing I'm not that keen on, is using the 13/8mm Ethos in 1.25" mode (although it works flawlessly)

Is it the overall length?

[Damo636]

Is it the overall length?

It probably is the length as much as anything, its just a bit unwieldy looking!

[Naemeth]

It probably is the length as much as anything, its just a bit unwieldy looking!

I suppose it would be good in an SCT or refractor, puts the eyepiece at a nicer height!

Did you sell the Powermate then?

[Damo636]

I sold it some time ago to fund another astro goodie (can't even remember what now). In hind sight, probably not the wisest decision I've made to date!