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What do you think of the 2" Wollensak 1.5X shorty barlow

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#1 markcasazza

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Posted 11 November 2019 - 10:25 PM

I've just done a major upgrade to my EP collection. My new premium EPs include:

  1. Tele Vue 31mm Nagle type 5
  2. Tele Vue 13mm Ethos 100
  3. Tele Vue 5mm Mager type 6

I've been seriously considering a 1.5X Barlow to fill in this missing focal lengths:

  1. 31 MM
  2. ~21 MM (31MM X1.5)
  3. 13 MM 
  4. ~9 MM (13MM X 1.5)
  5. 5 MM
  6. ~3MM (5MM X 1.5)  This is not really useful

This would let me sell my ES 18MM 82 degree EP that I never loved to help the wallet recover.

 

I'll be using these in two scopes

  1. Celestron C11 (11" f/10 focal length 2794MM)
  2. Star Master 20 (20" f/4.5 focal length 2286MM)

I have not found any other 1.5X 2" barlows. If you know of some, point me to them. The price is right and the other Wollensak items I bought performed well, but these Tele Vue EPs are in a whole new class.

 

https://www.surpluss...tem/L3948D.html

 

 

 



#2 wrnchhead

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Posted 12 November 2019 - 12:46 AM

I like the wollensack stuff I’ve gotten, but only because the price was right. The description says coated achromatic lens, plus the shorty design. I wouldn’t personally want my Ethos etc limited by that. I’d go for a powermate or Siebert Optics Barlows.
https://www.sieberto...cs-barlows.html

Now to frame my post, I’m no seasoned optician. I haven’t used his stuff but the page sure sells it!

Edited by wrnchhead, 12 November 2019 - 12:49 AM.


#3 nicoledoula

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Posted 12 November 2019 - 10:32 AM

THIS (or the Astro-Tech version sold by astronomics) is very versatile and is a known quantity. https://agenaastro.c...arlow-lens.html) Does 1.5X as well.


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#4 jturley80

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Posted 12 November 2019 - 11:51 AM

Would you want to barlow a 31T5?



#5 MitchAlsup

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Posted 12 November 2019 - 03:11 PM

Would you want to barlow a 31T5?

I do it all the time. It is the easiest way to get a 15.5mm 82º FoV.

 

Besides, if your guest does not like the views, you have the weapon at hand to change his mind.....


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#6 markcasazza

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Posted 12 November 2019 - 08:05 PM

Besides, if your guest does not like the views, you have the weapon at hand to change his mind.....

 

Funny!  The GSO working at 1.5X would only work with the hand grenade (31T5) because the other two EP are really 1.25" EPs. I'd also really prefer not to be threading things as I have gloves on much of the year and it is too easy to cross thread the EP.

 

I'm struggling figuring out the SO web site, but I will spend some more time on it. I was concerned the a cheap barlow would have aberrations on the edges and with these EPs that is what it is all about. Also, that fast scope is new to me. The C11 has been my primary visual instrument for over 15 years.



#7 wrnchhead

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Posted 12 November 2019 - 08:18 PM

I am not in love with that website either lol. I am going to get one his his barlows though, soon. 

 

I have that same Astro tech Barlow, and it is good. I don’t find the threads to be too much of a problem. They aren’t too awfully fine. 


Edited by wrnchhead, 12 November 2019 - 08:20 PM.


#8 markcasazza

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Posted 02 February 2020 - 10:50 PM

I have a great story about Harry Siebert. I got the 1.5X 2" barlow and it kidney beaned on me. Harry was happy to take it back, but he asked me to test it on some other scopes and EPs so he might better understand the problem. I obliged and he pondered the problem and actually sent me back a new improved 1.5X barlow to test. Free returns on him if it failed. And it PERFORMS!!!  Even in my 31mm type 5 Nagler and 13mm Ethos on an f/4.3 scope it provides a great image all the way to the edge with no sign of vignetting or distortion. I used NGC1976 and a bright star in the field as my test subjects. I strongly encourage you to get his Barlows. He just saved me buying two TeleVue EPs to fill that gaps between 31 and 13 and 5.


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