Telescope Basics 5 (of 6): Learn the basics about barlow lenses for telescopes

Barlow lenses are an inexpensive - and often effective - way to increase the magnification and eyepiece collection of amateur astronomers. In this video, David Fuller of "Eyes on the Sky" takes the viewer through the various types, caveats and benefits with using them, as well as what to look for when shopping for one.

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[Eyesonthesky]

Thanks for the nice comment, and you're very welcome. Glad these helped! :-)

[Eyesonthesky]

The "H" stands for Huygens lenses, the "SR" is a Ramsden. Both are simpler, two-lens element designs. For your 1000mm f/l telescope, they will work ok for now. Plossls in longer focal lengths will be better at some point - a 25mm and 16mm, perhaps. TMB, Orion, Zhumell and Astro-Tech all have decent "planetary" type eyepieces with shorter focal lengths with better eye relief. A 9mm and 6mm might be worth getting for those at some point. I'd suggest any of those to upgrade your eyepieces.

[carollshelby]

LOVE IT! I never thought of putting my Barlow before my star diagional that is awesome!

[jesuschuycampos]

I have an Orion FunScope which I received as a gift.

Specs (for those who don't know); A reflector scope. Comes with an
Optical Diameter 76mm, a Focal Length 300mm; Focal Ratio f/3.9, and
comes with two 3-element Eye Pieces (20.0mm (15x), 10.0mm (30x)). Its
highest useful magnification 152x.

Recommend folks see his video on this scope: "Orion Funscope / Celestron
Firstscope review/comparison"

I love it's portability and that sits nicely on my tripod, but like
everyone here, I would like to improve my experience.

I'm not a fan of wasting money on poor products, since sooner or later
it will cost me, but I neither want to spent a ridiculously amount of
money.

Based on your videos (IMHO they are great introduction to this hobby!!),
I should consider a shorty Barlow fully multi-coated lens. Based on the
lenses I have, it should be a 3x or 5x Barlow lens.

My goals is to be able to see the rings and moons of Saturn. (Just like I
use to, with an old refractor scope I once had)

Amazon results gave me few results of brands I'm familiar with:

Celestron 93428 X-Cel LX 1.25-Inch 3x 3-element apochromatic Barlow
Lens (~$65)
Orion 8707 High-Power 1.25-Inch 3x 4-Element Barlow Lens (~$134)
Orion 8715 High-Power 1.25-Inch 5x 4-Element Barlow Lens (~$175)

Do you have any advice on these Barlow lenses, or should I consider a
different vendor/model for my FunScope?

[Eyesonthesky]

Hi Diane - certainly those without glasses can use eyepieces with good eye relief. The eye relief of most eyepieces is not so long that it is difficult to see objects through them. The challenge is when eye relief is too short, and either those with glasses - or even those without - have difficulty getting close enough to the lens to see the entire field of view.

[obx]

Just realized that I was putting my shorty in the wrong place (that's what she said), I placed in behind instead of before.. thank you EOTS.. Great videos..

[Riloo]

oh thanks for telling me cause i was using my barlow lens opposite of my telescope for 1 month and thats why i was getting blurry image of the moon :DDDD

[guanqiuping]

thanks for the information..I'm the new user of telescope and find difficulties in set up my telescope and don't know the differences of each eyepieces, erecting eyepieces and barlow lens

[Eyesonthesky]

Andrés, it is not a hard and fast rule. A short one or a long one can be suitable for a reflector. The one thing to be careful of is reflectors that have very short focuser tubes - a longer barlow may wind up in the incoming light path. But for most telescopes, this is not a problem.

[Eyesonthesky]

Yes Chris - it just magnifies more. Just don't exceed 50x - 60x per inch (or per 25mm) of aperture.

[jinxyable]

You should make two more sereis of multiple videos like these. Talking about filters(planetary, solar, lunar, skyglow and Nebula) and Astrophotography(Film, digital Cameras, Camera(or video)eyepeices and ccd's and autoguiders)you could also talk about ccd filters RGBL and Alternates for ccds as well.

[agendaOFpeace]

i am new to stargazing so i don't even know how to attach the lenses to the telescope. i have a celestron cpc1100. is there a video out there that explains how to attach the barlow and lenses? thanks for any help, mark

[SixStringsCovers]

Nice video and explaining. I own Omegon Mightypak 90/1000 with a 25 mm eyepiece and the maximum zoom is 180x. How do I mount my Barlow 5x lens to my telescope to get the maximum zoom? I think It will be 200x.
Do you think the lens is too big for this telescope and get Barlow 2x instead? What other eyepiece do you recommend for zooming and landscape shooting?

[hyperzombie]

I have a 30mm a 12.5mm and a 8mm and a barlow 3x and an erecting eyepiece what do I use for looking at planets like Jupiter or the moon?

[Eyesonthesky]

Because that telescope comes with the 10mm that would effectively be the same as a 20mm with a 2x barlow, and since a 2x barlow put the magnification at 200x, which is really beyond what that scope should do (175 is the practical max), I would suggest a 1.5x or 1.8x barlow.

[janakiyeluripati]

Hi David, nice informational video. I'm planning to buy exploreone 50mm kids telescope for my six year old daughter at 35$. Will this work fine and still have decent view of the planets let me know. I'm on a shoe string budget

[miscellaneous]

I own a Celestron 130 telescope with 10 mm (33 x) and 20 mm (66 x) eye piece. I just wanted to know which barlow lens I should buy, which would improve the magnification without any degrade in picture clarity. Thanks

[wayangede]

Hello, Can we use eye piece of binocular or riffle scope to eyepiece of telescope?

[DavidSanchez-bfsz]

Thanks for finally explaining the difference between short and long focus. Also, how to install long Barlow on a refractor. I will test that out.

[greenglassrose]

David Question? If you would have a better eye piece, would I have a better view of the planets ect.. ..Your eyepieces (eye relief, ) From what I understand there for people with eyeglasses! can a person without glasses use them to? Your videos, very clear about explaning the subject, Thank you .