Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Small, short, lightweight 3x barlow?

  • Please log in to reply
6 replies to this topic

#1 Roger Corbett

Roger Corbett

    Viking 1

  • -----
  • topic starter
  • Posts: 732
  • Joined: 07 Mar 2013

Posted 19 September 2019 - 11:50 AM

Looking for a 3x Barlow for my Astroscan (a rich field, 4 1/8, f/4.24 scope).

 

I own a 3x Televue Barlow and recently bought a Celestron 3x Xcel one.  It's a good Barlow and my first views with it have been fine. 

 

Alas, I've discovered that the Celestron, like the TV, is a tad too heavy and long for the Astroscan — and, so, throws it out of balance.  (The 'Scan is a ball mount, so if an eyepiece-Barlow combo sticks out a ways, the scope has a tendency to rotate.).  The Celestron is about 3 1/2 inches long and weights 143 gms or slightly over 5 ounces.

 

My 'Scan is a good one, capable of higher magnification.

 

So, the quest is to find a small, short, but decent 3x Barlow.  (I already have a good 2x shorty,)

 

I've owned a couple of 3x shorties in the past, each of which had some issues, but I have little idea what's available these days, and maybe things have improved. 

 

Any suggestions?


  • lionel likes this

#2 lionel

lionel

    Ranger 4

  • *****
  • Posts: 363
  • Joined: 12 Aug 2007
  • Loc: Delaware

Posted 19 September 2019 - 12:52 PM

You could put out a want ad for a 2.8x Klee...a very compact (2 1/2" long, 93 gm), 3 element Barlow once sold by University Optics and now discontinued. It is very sharp and works seamlessly with my Type 6 Naglers and Deloses for high power viewing in my refractor and dob. Its limitation is that it will start to vignette an eyepiece with a field lens larger than a 13T6 Nagler.

 

Lionel


Edited by lionel, 19 September 2019 - 01:23 PM.

  • izar187 and Roger Corbett like this

#3 izar187

izar187

    Soyuz

  • -----
  • Posts: 3919
  • Joined: 02 Sep 2006
  • Loc: 43N

Posted 19 September 2019 - 05:27 PM

Looking for a 3x Barlow for my Astroscan (a rich field, 4 1/8, f/4.24 scope).

 

I own a 3x Televue Barlow and recently bought a Celestron 3x Xcel one.  It's a good Barlow and my first views with it have been fine. 

 

Alas, I've discovered that the Celestron, like the TV, is a tad too heavy and long for the Astroscan — and, so, throws it out of balance.  (The 'Scan is a ball mount, so if an eyepiece-Barlow combo sticks out a ways, the scope has a tendency to rotate.).  The Celestron is about 3 1/2 inches long and weights 143 gms or slightly over 5 ounces.

 

My 'Scan is a good one, capable of higher magnification.

 

So, the quest is to find a small, short, but decent 3x Barlow.  (I already have a good 2x shorty,)

 

I've owned a couple of 3x shorties in the past, each of which had some issues, but I have little idea what's available these days, and maybe things have improved. 

 

Any suggestions?

Honestly, a better way to go may be an ep for the magnification you seek. IMHO.

Lots of small newts can have issues with barlows to higher magnification.

Often the focusers just are not up to the weight.

Nowadays there are options in short focal length ep's, far easier to look thru than tiny orthos from yesteryear.

Plus lighter in weight than ep with barlow.

When a modest little scope is a keeper, then it is worth an ep or two... specifically for higher power. IME.

 

If a barlow is the preferred option, then definitely the 2.8x Klee, with a light weight ep.


  • Roger Corbett and PatrickVt like this

#4 SteveG

SteveG

    Cosmos

  • *****
  • Posts: 7815
  • Joined: 27 Sep 2006
  • Loc: Seattle, WA

Posted 19 September 2019 - 07:07 PM

This 2.6 oz Meade barlow will work. 

https://amzn.to/2kvJLPG

 

It will also require about 11.5 mm of inward focus travel. Additionally, it will vignette if used with a 26 mm plossl. It does fine with shorter focal length plossls. 

 

Optically it does very well from my tests - I've tested (4) different 3x barlows.


  • izar187 likes this

#5 Barlowbill

Barlowbill

    Viking 1

  • *****
  • Posts: 520
  • Joined: 05 Apr 2018
  • Loc: Tulsa, Oklahoma

Posted 20 September 2019 - 09:08 AM

SteveG is right on about the Meade 3X.  I like mine just fine.  I also like my University 2.8X Klee.  I should get rid of all the others but I'd have to change my name.


  • izar187 and Roger Corbett like this

#6 25585

25585

    Fly Me to the Moon

  • *****
  • Posts: 5532
  • Joined: 29 Aug 2017
  • Loc: In a valley, in the UK.

Posted 20 September 2019 - 09:11 AM

Orion Trimag is a good 3x



#7 Roger Corbett

Roger Corbett

    Viking 1

  • -----
  • topic starter
  • Posts: 732
  • Joined: 07 Mar 2013

Posted 20 September 2019 - 12:18 PM

Great help!

 

Chuckled over Barlow Bill's post!   At one time, I had over a dozen Barlows and could have used a “Barlow Roger” moniker!  Alas, I decided that I had too many eyepieces and Barlows and winnowed stuff out.   I let go several that I should have kept.

 

I figured out something key —  by raising the two of the tripod legs slightly, I could eliminate most of the droopsy problem caused by the Xcel 3x Barlow with the Astroscan.  So, I likely can use the Xcel 3x for planets, on occasion.  But a shorter one could still be useful. 

 

One big advantage to using a Barlow, as I understand it, is that it changes the effective focal ratio of the scope, thereby cleaning up some eyepiece aberrations.  In essence, with a 2x, the Astroscan becomes an f/8.5 and with a 3x, it's f/12.7.  Or, the Z100 4” f/4 becomes f/8 and f/12.

 

Still, I like the idea of getting a shorter focal length eyepiece as futzing with Barlows is often a nuisance.  Many have Barlows or Barlow like lenses built in.  As noted, they would be smaller and, by having a shorter moment arm than an eyepiece-Barlow combo, would cause fewer issues.  I could also pair it, as needed, with a small, light, shorty 2x I have that works well.

 

In recent sessions under the stars, I've rediscovered that most of my observing is at lower powers, anyway, where a Barlow isn't necessary.

 

As to which 3x Barlow...  

 

Lots of people like the Meade 3x #128 shorty.  Thanks for touting it.  I actually have it in my cart at an astro store.  But I've owned it before.  Now, the one I had may have been a bad sample, but it had field curvature issues on the Moon that other 3xs such as the 2.8x Klee and Antares 3x didn't have.  The Klee, though, had vignetting or blackouts on the Moon, but that was with a 25mm eyepiece, so too long a focal length.  I did note that the Klee required only slight in-focusing — a big plus — whereas the 3x Antares required HUGE amounts of out focusing, dangerously large amounts!  That one also magnified more like 3.4-3.6x. The Meade 128 required lots of in-focusing.

 

I wonder what the closest Barlow is to the Klee these days.  I don't see them come up very often!

 

I may just have to try the Meade, the Klee  or both again, unless there's a more recent option!




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics