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Explore Scientific 1.25" 2x Focal Extender / Barlow # FE02-125

4.8 (11 Reviews) Read Reviews Write Review
Brand Explore Scientific
Part Number FE02-125
Availability available

Product Info

Manufacturer Description

Increase Your Magnification Without Sacrificing Magnification Factor or Eye Relief

A Focal Extender does exactly what the name implies; it extends the effective focal length of the lens that it is used in conjunction with, thus producing higher magnifications for imaging and visual applications.

Focal extenders are similar to a Barlow or tele-negative lens, but there is one important difference between the two that you will want to take into consideration, especially if you plan to use the Explore Scientific Focal Extender for imaging and astro-photography.

When you use a standard Barlow or tele-negative lens to increase the magnification of your optical system, your results will be dependent on where you place the Barlow in the optical chain. For instance, if you put a 2x Barlow lens in front of your diagonal instead of behind it (Barlow-Diagonal-Eyepiece as opposed to Diagonal-Barlow-Eyepiece), you won't get 2x magnification in both set-ups. The magnification varies with placement. However, with an Explore Scientific Focal Extender, even if the distance is changed, the magnification remains the same. You can place your Focal Extender anywhere along the optical chain between an eyepiece or a camera, and if you are supposed to get 2x magnification, you will get 2x magnification.

When it comes to imaging, this is a critical difference, because you may want to introduce an accessory like a flip mirror or filter wheel in between the Focal Extender and a CCD camera, which would increase the distance to the focused image. This difference in design allows users to rest easy, whether they are pumping up the magnification of a lower power eyepiece for visual observations or using their Explore Focal Extender in imaging applications.

Explore Scientific Focal Extender Highlights

  • More Magnification Choices without Sacrificing Eye Relief: A good Focal Extender adds some real versatility to your telescope accessory line-up. First of all, it allows you to increase the magnification of any eyepiece with the same barrel size that you already own. In other words, 3 eyepieces offer 6 magnification choices with the addition of a focal extender. Secondly, most of the time, lower magnification eyepieces have better eye relief than higher power models. When using a focal extender to increase your magnification, you get to enjoy the generous eye relief of the lower power eyepiece, and that's quite a bonus, especially for eyeglass wearers or for those with fast telescopes who can really push high magnification eyepieces. Remember, we make focal extenders in 2X, 3X and 5x models, so there is something for every style of telescope.
  • Optimized Optical Design: Explore Focal Extenders are optimized through each design, fabrication, and testing process to produce high contrast, high resolution images.
  • Durable EMD Coatings & Finishing Touches: Each of the four elements in your Explore Scientific Focal Extender is fully multi-coated with EMD (Enhanced Multi-Layer Deposition) enhanced coatings, resulting in bright, sharp images. And like Explore Scientific eyepieces, the lenses are edge-blackened to eliminate internal light scatter. When you add a high quality focal extender to your optical chain, the entire optical package is optimized for the highest light transmission and contrast, and will deliver crisp, clean images to your eyepiece or imaging system.
  • Tapered Barrel for Extra Security: The insert barrel of each extender is double-tapered to allow smooth insertion to, and removal from, a telescope's eyepiece holder, focuser or diagonal, however the wide dimension of the taper helps prevent the focal extender from falling out of the telescope should the set-screw holding it in place become loose.


Producing optics for amateur astronomers that can be relied upon to deliver research-quality images requires a solid design, careful fabrication, multiple tests, and continued diligence to make sure we are always doing everything we can to produce a cutting edge, quality product. This is what we do at our facilities at Explore Scientific, and to insure your satisfaction, we back each eyepiece with the Explore STAR Transferrable, Extended Life of the Product Warranty, so you can keep exploring!

Key Specifications:

  • Total height = 3.89" / 98.7mm
  • Length of 1.25" nosepiece = 1.56" / 39.6mm
  • Weight = 9.0oz / 256g
  • Clear lens aperture = 0.67" / 16.9mm
  • Made in China

Reviews

4.8 (Based on 11 Reviews) 100% of reviewers recommended this product.
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    1. Bigfoot

      Bigfoot New Member

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      Review by Robert Z.
      1537085986
      Sep 16, 2018

      5.0 Ideal solution

      Pros:

      Cons:

      Comments:

      Although I already possessed an Explore Scientific 2", 2X focal extender, I needed a way to avoid having to buy expensive 2" color filters when I already had a assortment of 1-1/4" filters for planetary imaging. I hoped that this piece of equipment would be just as good as the 2" version, and it appears to be. So, I'm quite satisfied.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    2. Guest

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      Review by Kristian N.
      1510538228
      Nov 12, 2017

      4.0 Great Focal Extender

      Pros:

      Cons:

      Comments:

      I bought this X 2 Focal Extender to use with my 1.25 eyepieces. It is mechanically a very high quality. It is excellent on most DSO. I have not had a chance to use it on planets yet due to the time of the year. I do notice a hint of light scatter on bright stars as compared to using the same eyepiece without the extender - hence 4 stars instead of 5. Overall a great value though.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    3. Ronald Zincone

      Ronald Zincone New Member

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      Review by Ronnie Z.
      1508983078
      Oct 25, 2017

      5.0 Great piece of glass!

      Pros:

      Cons:

      Comments:

      Another great optic from Explore Scientific and sold by Agena

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    4. Guest

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      Review by Derek of Westport, IN.
      1464393600
      May 27, 2016

      5.0 Quality Barlow

      Pros:

      Quality Lenses,Strong Construction

      Cons:

      Heavy

      Comments:

      This Barlow has worked great for me and is a nice compliment to my other ES eyepieces. I use it for visual and imaging work. The compression ring doesn't scuff the nose of your camera or eyepiece.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    5. Guest

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      Review by Karl of Northern Illinois.
      1436054400
      Jul 4, 2015

      5.0 Quality

      Pros:

      Quality Lenses,Strong Construction

      Cons:

      Comments:

      Excellent build quality. Fit and finish are top-flight. This is a heavy and long optical accessory. It will probably require rebalancing. Being a focal extender, it can be placed anywhere between the eyepiece and the scope and produce the same multiplication factor. I recommend it.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    6. dogstar

      dogstar New Member

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      Review by Starthrower of NH.
      1401840000
      Jun 3, 2014

      5.0 Optically unobtrusive, but weighty

      Pros:

      Strong Construction,Easy to Use,Quality Lenses

      Cons:

      Comments:

      This is an excellent focal length reducer. I would put it up there with the TV Powermates, and I believe they have similar optical design. If planning an EP/Barlow suite of optics be aware that this is a bit bulky, so for smaller scopes on lighter mounts the combo weight could be problematic. That said, it maintains eye relief and doubles the mag, with no discernable loss of visual image quality. Another great ES product!

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    7. Guest

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      Review by Dude of Holland.
      1395964800
      Mar 27, 2014

      5.0 Excellent quality barlow/extender

      Pros:

      Easy to Use,Accurate,Strong Construction,Quality Lenses

      Cons:

      Heavy

      Comments:

      Excellent optical quality. Easy to insert and remove eyepieces by loosening only 1 thumb screw. Strong construction, but a bit heavy. Works great!

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    8. Guest

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      Review by Mat of UK.
      1391040000
      Jan 29, 2014

      5.0 Fantastic value for money

      Pros:

      Quality Lenses

      Cons:

      None

      Comments:

      I must say I'm very satisfied with my 2x focal extender/Barlow. The overall fit and finish of it is first class and the coatings are very good. I have used it for planetary imaging with my mono cam and for visual observations and it performs superbly. I have many ES products and they all provide excellent value for money when you consider how well they perform but for me this is the star performer 10/10.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    9. Guest

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      Review by michael aldan of Durban, South Africa.
      1384819200
      Nov 18, 2013

      5.0 ES 2x Focal Extender, Excellent

      Pros:

      Quality Lenses,Strong Construction,Accurate

      Cons:

      Heavy

      Comments:

      After much pondering I decided on the ES Focal Extender.
      My reason? All the raving reviews on cloudy Nights and other astronomy forums.

      I ordered the ES for my Skywatcher 10" f4.7 dob, and what a difference this extender makes!!

      Eyepieces (my Agena Starguider ED's) become clearer and sharper, no seagulls nor the annoying kidney bean effect.

      This extender is of superb quality, very well made, quite heavy but durable.

      The aww factor is in using this extender,

      It is top notch glass for nearly one fourth of the price of a TV Powermate.

      I am absolutely thrilled with this ES extender.

      Definately a winner, no doubt about it..

      michael

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    10. Guest

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      Review by Steve of Coldiron, KY.
      1381795200
      Oct 14, 2013

      4.0 Great Value

      Pros:

      Strong Construction,Quality Lenses

      Cons:

      Comments:

      Superb construction quality. Admittedly, I was very pleasantly surprised.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    11. Guest

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      Review by Dave of Upstate NY.
      1363996800
      Mar 22, 2013

      5.0 Excellent 2x Barlow

      Pros:

      Quality Lenses,Easy to Use,Strong Construction

      Cons:

      Comments:

      I use the Explore Scientific 2x barlow with my Vixen 140mm Refractor for deep sky and lunar observations. It works well with every eyepiece I've used it ranging from plossl to premium eyepieces such as XW's. In all cases it improves edge performance of the eyepieces. No aberrations are introduced with the use of the barlow. I've compared it with a 2.5x Powermate and the only difference in performance I see is magnification. This is a 4 element telecentric design so the ES 2x barlow will not cause increased exit pupil sensitivity and it does not vignette with longer FL eyepieces. Construction of this barlow is outstanding. I particularly like the large locking screw for the compression ring. It is very easy to use with gloves on.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

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      Specifications

      Manufacturer Explore Scientific