Best Telescope Barlow Lenses in 2020



Celestron Omni 2X Barlow Lens Review:


Users who don't know what they are doing or talking about is really getting on my wick. It could be a review on the latest electronic device or a set of spoons! But this explains the long amble to my final remarks on the Celestron 2x Omni Barlow in this review.

Observational astronomy has been my avocation for 33 years with hundreds of dusk to dawn sessions, and thousands of hours at the eyepiece.

I am afraid that most people who purchase a Barlow lens have performance expectations that are naive, or are trying to correct the mistake of having purchased a telescope whose f/ratio is so fast as to make any high magnification observations disappointing. An f/5 telescope, for instance, is fine for observing deep sky objects in a wide field of view. An f/15 refractor is best suited for planetary, lunar and binary star observations where high magnifications and high contrast images are required.

As we move through a range of eyepieces from low to high power what does the user notice most? It is the eye relief. The eye relief of a 32 mm is long enough even to use glasses. But as we drop down to 6 mm, 5 mm, and 4 mm the eye lens becomes very small. You must move in so close as to sometimes touch the eye lens with one's eye lashes. If you wear glasses, they must be removed to get close to the eyepiece. Now any malady your eyes suffer from are uncorrected. This may introduce your chromatic aberrations, serious astigmatism, &etc, to the telescopic image.

Of course there is the telescope itself. The best instruments under good atmospheric conditions can, at best, employ 50x to 60x (power) per inch of aperture. Further magnification is called "empty magnification". Why? Because you have already reached the theoretical resolution limit of the telescope. More magnification reveals no more detail. The images just get bigger, darker and fuzzier.

For instance, a 4" telescope will have an optical limit of 240x. An 8" telescope can theoretically achieve 480x. But there are so many variables to consider. Is the scope a Schmidt-Cassegrain, a Newtonian (is it a long or short f/ratio?), is it a refractor (long or short f/ratio)? What are the seeing conditions? An absolutely clear sky can have horrible "astronomical seeing" (unsteady air) which causes stars to twinkle, and any planetary or lunar image to go from sharp and crisp to a blob. You can throw those theoretical dictums right out the window!

The typical introductory or moderately priced scope will come with "run-of-the-mill" eyepieces of 25 mm and 10 mm that are not of high quality. Even a good quality Barlow will make flaws in poor quality optics stand out like a sore thumb. If it was not a good eyepiece at 10 mm what can you expect when it is a Barlowized 5 mm?

But we purchased a trusty, magical Barlow with the hopes of seeing Neil Armstrong's foot prints on the moon with our Barlowized 2 mm at 750x! Is it any surprise that novices are quickly jaded with the hobby altogether out of ignorance and unrealistic expectations, or perhaps lay the blame on their new, shiny, slick Barlow?

Barlows come in 2x, 2.5x, and 3x. Some are absurdities at 4x or 5x! Barlows are designed to extend an instrument's focal length. But in practice their primary function is to obtain higher magnifications with low power eyepieces while still retaining the low power eyepiece's long eye relief. This maintains comfortable viewing with high magnifications even while wearing glasses. Remember my earlier comments regarding eye relief and glasses wearers? Barlows are not intended to be used with the entire range of eyepieces in your kit.

A Barlow's performance excels with eyepieces from 32 mm down to 12 mm. That Barlowized 12 mm is now a 6 mm, but retains the eye relief of a 12 mm. 12 mm or 10 mm eyepieces are the absolute end-of-the-line for employing a Barlow and to expect any degree of visual integrity. Beyond that range and you are just playing with your "toys" and abusing them at that! A Barlow is a tool of convenience not a magic wand.

Yes, this is a review on the Celestron 2x Omni Barlow.

My neighbor just got his in the post today. He lent it to me to test. I compared it with a 60-year-old original Goodwin Barlow, an early Parks Barlow and a Unitron Achromatic Amplifier. I compared a full range of Unitron Orthoscopics, a set of König wide-field eyepieces, and a set of Vernonscope "limited edition" brass Brandons which use special glass that is hand selected. Brandons are the favorite eyepiece among professional astronomers.

The telescope was a 100 mm, f/15 Unitron refractor with an objective lens manufactured by Pentax for Unitron. These Pentax objective lenses are considered to be Unitron's "jewels-in-the-crown" objectives of perfect quality.

What did I conclude? That Celestron's Omni 2x Barlow was spot on, with no aberrations or errors even at the very edge of the field. What aberrations did become apparent were with high power eyepieces that shouldn't be attached to a Barlow. EVER! For the most part, it was the quality of the eyepieces that was being tested more so than the Omni Barlow. The eyepieces in question being pushed beyond their operational limits.

The Celestron 2x Omni Barlow is a beautifully crafted Barlow, especially for the price. So if you have problems with this Barlow, it ain't the Barlow's fault.



Orion 1.25" Shorty 2X Barlow Lens and Camera T-Adapter Review:


As advertised. Shipped fast and works great. Originally bought as an experiment piece to see what an 8 inch Dob telescope can do. I took this lens outside and simply looked into the lends, focusing it on a street lamp at night which was across the street. The magnification and clarity is great, and this will be used quite extensively. At the top, it has threads for me to screw on an adapter if I want to. It's main intent was to help see the stars better, and it lives up to that expectation. The second part of the purchase was to aid in the experimentation of taking clear video with an 8 in Dob telescope. That is a work in progress.



Celestron 93428 X-Cel LX 1.25-Inch 3x Barlow Lens (Black) Review:


 Celestron Barlow Lens 3X 1.25in X-cel LxI purchased this 3 Times Barlow X-Cel LX with the intention of obtaining closer live detailed images from the Moon with a Webcam made to fit the X-Cel LX Series eyepieces and it works great! This video is in 720P and is mounted on the 9mm X-Cel XL Eyepiece.Without the Barlow then With the Barlow



Orion 08711 Shorty 1.25-Inch 2x Barlow Lens (Black) Review:


Orion products are good to adequate (and their customer service is legendary), the shorty Barlow is one such product. This might be one of the most widely used Barlow lenses and is highly recommended.
Complaints against this product are probably due to the slightly large eyepiece opening. Probably to accommodate a wider variety of eyepieces and components the over-sized opening can cause slight misalignment of eyepieces and creates a small amount of astigmatism. This is not noticeable or problematic with visual use, but can cause a problem if used with photographic or other equipment.
I tried to use this Barlow to increase magnification on a guide scope/camera and the resulting astigmatism was annoyingly noticeable. With a larger eyepiece or camera barrel alignment might be improved. I suspect the lenses used are excellent and not the cause of the astigmatism.



Gosky 1.25 Inch 2X Fully Blackened Metal Barlow Lens and Camera T Adapter for Telescopes Eyepiece - Accept 1.25inch Filters-Also Can Be Used for Astronomical Photography - Coated Review:


Purchased after reading Brett's review:
"Well built, solid, especially for the price. The lens gives a good clear vision and is also removable so the tube could also be used as a short extension tube. So it's saved me a bit of money because it's like two items in one."

It has the features I wanted:
1. Being able to remove the lens and insert the lens directly into the diagonal or a zoom eyepiece or a regular eyepiece to give it different magnifications (experiment a little).
2. Use the way it comes as 2x magnification
3. Remove the lens and use it as an extension tube (about half the price of Orion's extension tube)
4. T adapter (which I am not planning on using at this time)

I may have not listed all but I tried. Great durable product at low cost. Thanks Gosky.

P.S. I purchased their zoom eyepiece for about half the price of Celestron and Meade. Great product for the price also.
Their variable polarizer works great also.



SVBONY 1.25 inches 5X Barlow Lens Fully Blackened Metal Multi Coated Broadband Green Film with M42 Thread for Standard Telescope Eyepiece Astronomy Review:


My telescope is 5'' f/5 newtonian reflector.
Its usable maximum magnification is about 260X.
But, bundled high power eyepiece gives only 65X.
Whenever watching moon surface, I wanted more magnification.
In theory, 4X barlow lense should be ideal, utilizing maximum potential, but not more.
In reality, even 3X barlens was out of reach with its prohibitive price.
(Considering the price of telescope itself.)
With the help of amazon's powerful sorting by price (from low to high), I met this lense.
The price is good and seller's specification says it is APO design, which is typically high quality.
But, there was a very negative review from other user.
Anyway, I wanted utilize all the potential of my telescope,
and I bit the bullet and tried it myself.
Fortunately, the result was rewarding.
It is a little long and heavy, but it gives high magnification power and clear image quality only for $25.
Considering its wonderful price tag, I give it 5 stars.

Con
This lens is a little long and heavy that it easily breaks the weight balance of telescopes.
(So, negative review from other user who mentioned focal length has its own value.)
With weight balance broken, the telescope get unstable and pointing get a little tricky.
High magnification power of this barlow lens, make the problem worse.
Even the slightest movement from unstabilization also get magnified,
And the target gets out of the field of view easily.
There are 2 common ways to recover the balance.

1. Re-balancing
- Loosen the bolt holding the dovetail and adjust the positon and tightening the bolt.
- Check if balanced, and if not repeat it again.
- No additional monetary cost but irritating.
(You should go through this procedure whenever attaching this barlow lens.)

2. Attaching some magnet to the rear part of the telescope, fuctioning as a counter-weight.
- Purchasing some magnet means additional monetary cost, but remember?, this lens is such a bargain.
- Attaching some magnet is much more convenient than loosening & re-tightening a bolt,
and if the OTA does not have dovetail plate, this is the only way.
- In theory, about the same weight (as that of this lens) of magnet will be needed.
If not sure about the proper size of magnet,
purchasing multiple small magnets and adjusting the number of magnet attached, is a safe choice.
(Small magnets easily get sticked to each other as a bundle,
so handling a large number of small magnets is manageable.)

There is also a problem with too high magnification.
With 5X, it is so easy to go over the maximum capability of the telescope optics.
(Maximum usable manification is usually 2 * aperture in mm.)
And after the maximum, image get blurred.
In my case, this barlow lens and bundled high power eyepiece together gave about 120% of the maximum, and image quality get degraded a little.

Pro
At such a bargain price, it gives 5X magnification power with good enough image quality.
With low power bundled eyepiece attached to this lens, image quality is quite good.
With high power bundled eyepiece and this lens gives 120% of the maximum magnification,
and image get blurred a little, but I am happy to utilize all the potential of the optics.
Detailed view of the Moon surface is very satisfying.
It is good to keep portability with low focal length, and get high magnification, too, with this lens.

Caution
You need stable mount and well-aligned finderscope (or red dot finder).
It feels like the telescope got 5X more sensitive with this lens attached.
Unstability of the mount and misalignment of finderscope get also magnified.
That's why weight re-balancing is important.

Conclusion.
A little long and heavy. Easily breaks the weight-balance.
But after recovering the balance, it gives 5X magnification with good image quality.
It is a perfect fit for short focal lengh telescopes, which typically lacks magnification power.
If you need higher magnification, but worried about additional expenditure, I definitely recommend this lens.



SVBONY Barlow Lens 5X 1.25 inches Fully Multi Coated Metal Thread M42 for Astronomical Telescope Eyepiece Accept T Ring with 1.25 inches Interface Review:


Great. Decent quality for the price. The shaft that you insert into your optical tube is a bit short, not threaded either, which could cause a heavy eyepiece or camera attachment to weigh down the telescope. Make sure to use this only for clear viewing conditions, if theres any fog or ambient light or thermal radiation coming from the ground (i.e. don't set up over sand/dirt/concrete...), this barlow could produce a grainy image. In the right settings though I crater the moon and separated nebulas. Can make out storms on Saturn.



SVBONY 1.25 inches 2X Barlow Lens Doubles The Magnification Multi Coated Broadband Green Film with M42 Thread for Standard Telescope Eyepiece Review:


I have used this with Celestron COSMOS FirstScope Telescope for several months with satisfactory experience; and you can't beat the price. However, I hesitated in writing a review because I am inexperienced with telescopes despite good general knowledge about optics. But a recent encounter with Meade Instruments 216005 Polaris 127 EQ Reflector Telescope (Blue) has boosted my confidence, as I can compare this side by side with a Meade Barlow, on two different telesscopes.

The construct of this product, metal body and all, is very refined compared with the plastic body that comes with Meade. My untrained eyes cannot detect visible aberration in this VITE Barlow. In contrast, the Meade Barlow gives very obvious chromatic aberration when I tested both Barlows on Cosmos FirstScope as well as on Polaris 127EQ.

Meade is an established brand name. So this comparison weighs a lot in my mind even though Polaris is in Meade's low-end.

Update: I have since used this VITE on a much better telescope SkyWatcher S11600 Traditional Dobsonian 6-Inch (White). The scope's collimated parabolic mirror provides clearer images on the edge of field of view so it is easier to evaluate quality. I stack the 2x Barlow with the 20mm Kellner from the FirstScope and compare with the 10mm Plössl that comes with SkyWatcher. FirstScope's eyepieces are not as good as SkyWatcher's; stacking two optical elements together is generally worse that one piece of the same focal length. Even so, the Barlow combination compares favourably. (The picture of Jupiter and its four Galilean satellites is taken with the 4mm from VITE Telescope Eyepiece Set Aspheric 4/10/23mm 1.25" Wide Angle 62-Deg Fully Coated for Astronomical Telescope and the 2x Barlow on FirstScope.)



SVBONY Barlow Lens 5x Blackened Metal with T adapter M42x0.75 Thread for 1.25 inches Telescope Eyepiece for Superior Sharpness and Color Correction Review:


I have used this with Celestron COSMOS FirstScope Telescope for several months with satisfactory experience; and you can't beat the price. However, I hesitated in writing a review because I am inexperienced with telescopes despite good general knowledge about optics. But a recent encounter with Meade Instruments 216005 Polaris 127 EQ Reflector Telescope (Blue) has boosted my confidence, as I can compare this side by side with a Meade Barlow, on two different telesscopes.

The construct of this product, metal body and all, is very refined compared with the plastic body that comes with Meade. My untrained eyes cannot detect visible aberration in this VITE Barlow. In contrast, the Meade Barlow gives very obvious chromatic aberration when I tested both Barlows on Cosmos FirstScope as well as on Polaris 127EQ.

Meade is an established brand name. So this comparison weighs a lot in my mind even though Polaris is in Meade's low-end.

Update: I have since used this VITE on a much better telescope SkyWatcher S11600 Traditional Dobsonian 6-Inch (White). The scope's collimated parabolic mirror provides clearer images on the edge of field of view so it is easier to evaluate quality. I stack the 2x Barlow with the 20mm Kellner from the FirstScope and compare with the 10mm Plössl that comes with SkyWatcher. FirstScope's eyepieces are not as good as SkyWatcher's; stacking two optical elements together is generally worse that one piece of the same focal length. Even so, the Barlow combination compares favourably. (The picture of Jupiter and its four Galilean satellites is taken with the 4mm from VITE Telescope Eyepiece Set Aspheric 4/10/23mm 1.25" Wide Angle 62-Deg Fully Coated for Astronomical Telescope and the 2x Barlow on FirstScope.)